BBQ Mushroom Beetroot Burgers

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These burgers are built from chopped mushrooms, black beans, and short-grain brown rice, bound with a flax egg and panko, then seasoned with tamari and smoked paprika. A quick maple-and-apple-cider-vinegar beetroot relish goes on top. The honest reason to make them: the patties come together faster than most homemade burgers, and the relish uses ingredients you likely already have.

Why this recipe works

Two things carry this recipe. First, cooking the mushrooms until all their moisture is gone — not just softened, but genuinely dry with golden edges — concentrates flavor and prevents a soggy patty. Wet mushrooms will make the mixture slack no matter how much binder you add. Second, the 30-minute chill firms the patty before it hits heat, which means it holds together on a grill grate or cast-iron pan without needing to be babied. Skip that rest and you’re flipping a crumble.

Common problems and fixes

Patties fall apart when flipped: The mixture was too warm or too wet going into the pan. Press them firmly when shaping, make sure the mushrooms were cooked dry, and don’t flip until the bottom has a visible crust — at least 4 minutes on medium heat.
Relish is too thin and slides off: The beetroot released too much liquid. Cook it a few minutes longer over medium heat, stirring, until the liquid reduces to a jammy consistency that mounds on a spoon.
Center is dense and gummy: The brown rice was overcooked and too starchy. Use rice that’s just done — slightly firm grains hold their structure and give the patty a better texture than mushy rice does.
Smoked paprika taste is flat: Old smoked paprika loses its punch quickly. If yours has been open more than six months, use half a teaspoon more than the recipe calls for, or add a small dash of liquid smoke to compensate.
Patties stick to the grill: The grate wasn’t hot enough when the patties went on. Get it fully preheated and brush it with a neutral oil right before placing the patties — they’ll release cleanly once a crust forms.

Substitutions that actually work

Short-grain brown rice: Cooked short-grain white rice works and cuts prep time. Long-grain varieties are drier and make the patty more crumbly — avoid them here.
Black beans: Cooked lentils (not red — they go too soft) or kidney beans are solid swaps. Drain and pat them dry before using.
Panko breadcrumbs: Regular breadcrumbs work but produce a denser texture. Gluten-free panko is a reliable one-for-one swap if needed.
Fresh beetroot for the relish: Pre-cooked vacuum-packed beetroot (unseasoned, not pickled) cuts about 45 minutes off your time and tastes fine — skip the garnish of fresh beet greens if you go this route, not worth the extra dish.
Tamari: Regular soy sauce is a direct swap. Coconut aminos work but are sweeter; reduce the maple syrup in the relish by half a teaspoon to balance.

BBQ Mushroom Burgers with Beetroot Relish

Michelle Davis

Portobello or large cremini mushrooms form the patty here, seasoned for umami depth and cooked on a grill or grill pan until charred at the edges. A tangy-sweet beetroot relish and smoky paprika mayo go on top, bringing contrasting flavors to each bite. The burgers take about 40 minutes to make and suit both backyard cookouts and everyday dinners.

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Prep Time 55

Cook Time 41

Total Time 1 36

Course Main Course

Cuisine American

Servings burgers

Calories 672 kcal

Equipment

Chef's knife
Cutting board
Box grater or food processor with grating disc
Medium saucepan
Large skillet or grill pan
Mixing bowls
Measuring cups and spoons
Baking sheet
Parchment paper
Spatula
Basting brush

Ingredients

For the Beetroot Relish:

1 tbsp extra-virgin olive oil good-quality, fruity oil
½ cup red onion, finely diced about 1/2 medium
1 clove garlic, minced fresh, not jarred
2 cups raw beets (beetroot), peeled and coarsely grated about 2 medium beets (approx. 10 oz)
3 tbsp apple cider vinegar unfiltered preferred
2 tbsp pure maple syrup grade A amber
1 tsp Dijon mustard smooth, not whole grain
½ tsp fine sea salt
¼ tsp freshly ground black pepper

For the BBQ Mushroom Patties:

2 tbsp ground flaxseed freshly ground for best binding
5 tbsp warm water for the flax “egg”
2 tbsp extra-virgin olive oil, divided 1 tbsp to sauté, 1 tbsp to sear
1 lb cremini or portobello mushrooms, finely chopped wipe clean; avoid washing to limit moisture
½ cup yellow onion, finely diced about 1/2 medium
2 cloves garlic, minced freshly minced for best aroma
1 tsp smoked paprika Spanish pimentón dulce
½ tsp ground cumin
½ tsp kosher salt Diamond Crystal preferred
¼ tsp freshly ground black pepper
1 tbsp tamari or low-sodium soy sauce tamari for gluten-free
1 tsp vegan Worcestershire sauce optional, for depth
1 cup cooked short-grain brown rice, cooled short-grain helps binding
1 cup cooked black beans, rinsed and well-drained lightly mash in mixing
¾ cup panko breadcrumbs gluten-free panko if needed
2 tbsp fresh parsley, finely chopped flat-leaf preferred
1 tbsp olive oil for searing patties
¼ cup vegan BBQ sauce plus extra for serving; choose a smoky style

For the Smoky Paprika Mayo:

½ cup vegan mayonnaise choose a neutral, creamy brand
1 tsp fresh lemon juice brightens the sauce
½ tsp smoked paprika
¼ tsp garlic powder

To Assemble:

4 whole burger buns, split vegan brioche-style if available
1 tbsp vegan butter or olive oil for toasting buns
4 leaves crisp lettuce romaine hearts or butter lettuce
1 large ripe tomato, sliced heirloom when in season
8–12 chips dill pickle to taste
8–12 rings red onion paper-thin for crunch without bite

Instructions

Mise En Place (10 minutes): Wash and peel the beets, then coarsely grate to yield 2 cups. Finely dice the onions, mince the garlic, and finely chop the mushrooms and parsley. Set out all measured ingredients for a smooth workflow.
Start the Beetroot Relish (20 minutes cook time total): In a medium saucepan over medium heat, warm 1 tbsp olive oil. Add 1/2 cup red onion and sauté until just translucent, about 2 minutes. Add 1 minced garlic clove; cook 30 seconds until fragrant. Stir in 2 cups grated beets, 3 tbsp apple cider vinegar, 2 tbsp maple syrup, 1 tsp Dijon, 1/2 tsp sea salt, and 1/4 tsp pepper. Bring to a gentle simmer, then reduce heat to low and cook uncovered, stirring occasionally, until glossy and jammy, about 18 minutes. Remove from heat and let cool; it will thicken as it stands.
Make the Flax “Egg” (5 minutes resting): In a small bowl, whisk 2 tbsp ground flaxseed with 5 tbsp warm water. Let stand 5 minutes to gel.
Sauté the Mushrooms (8 minutes cook time): Heat 1 tbsp olive oil in a large skillet over medium-high heat. Add 1 lb chopped mushrooms and 1/2 cup diced yellow onion. Cook, stirring occasionally, until most moisture evaporates and edges take on a golden hue, about 7 minutes. Stir in 2 minced garlic cloves; cook 1 minute more until fragrant. Sensory cue: the pan should sound lively but not sputter; adjust heat to avoid steaming.
Season and Build the Patty Mix (10 minutes active): Off heat, stir in 1 tsp smoked paprika, 1/2 tsp ground cumin, 1/2 tsp kosher salt, 1/4 tsp pepper, 1 tbsp tamari, and 1 tsp vegan Worcestershire (optional). Transfer mixture to a bowl. Add 1 cup cooked brown rice, 1 cup cooked black beans (lightly mash as you mix), 3/4 cup panko, 2 tbsp parsley, and the flax “egg.” Mix until cohesive; it should feel slightly tacky but hold together when pressed. If loose, add 1–2 tbsp more panko; if dry, sprinkle in 1–2 tsp water.
Shape and Chill (30 minutes resting): Divide the mixture into 4 equal portions (about 1/2–3/4 inch thick). Place on a parchment-lined baking sheet and chill 30 minutes to hydrate and firm. This ensures clean edges and a tender, sliceable interior.
Sear the Patties (10 minutes cook time): Warm 1 tbsp oil in a clean skillet or preheated grill pan over medium-high heat (about 400°F / 205°C). Sear patties 5 minutes per side until well-browned, brushing each side in the last minute with vegan BBQ sauce for a lacquered sheen. Sensory cue: look for a mahogany crust and light caramelized edges.
Toast the Buns (3 minutes cook time): Spread cut sides with 1 tbsp vegan butter or a thin film of oil. Toast in the skillet or on the grill until golden at the edges, about 3 minutes (medium heat; aim for warm, crisp surfaces).
Mix the Smoky Mayo (2 minutes active): In a small bowl, combine 1/2 cup vegan mayo, 1 tsp lemon juice, 1/2 tsp smoked paprika, and 1/4 tsp garlic powder. Whisk until smooth and pink-hued.
Assemble: Spread smoky mayo on both bun halves. Layer lettuce, the mushroom patty, a generous spoonful of beetroot relish, tomato slices, dill pickle chips, and red onion rings. Add a final brush of BBQ sauce if you like extra smoke and sweetness. Serve immediately while buns are warm and patties are juicy.
Alternative Methods: Outdoor grill at medium-high heat (about 400°F / 205°C): oil grates well, sear patties 4–5 minutes per side, brushing with BBQ sauce in the final minute. Oven-baked option: bake on a parchment-lined sheet at 400°F / 205°C for 18–20 minutes, flipping halfway; finish in a hot skillet 30–60 seconds per side for a crisper crust.

Notes

Michelle’s Tips:

Dry-Sauté Mushrooms First: If mushrooms release abundant moisture, pause oil and cook them dry for 2–3 minutes to evaporate water; then add oil to encourage browning.
Better Binding: Short-grain brown rice acts like culinary “glue.” If substituting quinoa, add 1–2 extra tbsp panko.
Extra Smokiness: A drop or two of liquid smoke can be added to the BBQ sauce; use sparingly.
Faster Relish: Grate beets finely and simmer uncovered; a wider pan increases evaporation for quicker jamminess.
Gluten-Free: Use tamari and gluten-free panko; choose GF buns.
Soy-Free: Swap tamari/soy with coconut aminos and reduce maple syrup by 1/2 tsp to balance sweetness.
Make-Ahead: Patties can be formed up to 2 days ahead; keep chilled, well-wrapped. Relish keeps 1 week refrigerated.
For the cleanest slices, let patties rest 2–3 minutes after searing.
If your relish tastes too sharp, stir in an extra 1/2 tsp maple syrup off heat.

Nutrition

Calories: 672kcalCarbohydrates: 69gProtein: 13gFat: 39gSaturated Fat: 5gPolyunsaturated Fat: 4gMonounsaturated Fat: 12gTrans Fat: 1gCholesterol: 2mgSodium: 1407mgPotassium: 1298mgFiber: 11gSugar: 23gVitamin A: 1089IUVitamin C: 17mgCalcium: 129mgIron: 4mg

Keyword BBQ Mushroom Burgers, Beetroot Relish, Burgers, Grilling, Plant-based, Summer, Vegan

Tried this recipe?

Common questions

Can I make the patties ahead of time?

Yes — shaped, uncooked patties keep in the fridge for up to 24 hours, stacked with parchment between them. They actually cook better from cold than from room temperature, so there’s no need to let them sit out first.

Can I freeze these burgers?

Freeze them after shaping, before cooking. Lay them flat on a parchment-lined tray until solid, then transfer to a freezer bag. Cook straight from frozen over medium heat with a lid on for the first few minutes to heat the center through.

Do I have to use a grill, or can I cook these on the stovetop?

A cast-iron skillet or heavy non-stick pan works just as well as a grill. Medium heat, a thin layer of oil, and patience with the flip — the results are nearly identical, and cleanup is easier.

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