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BBQ Mushroom Burgers with Beetroot Relish

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 minutes
Cook Time 41 minutes
Total Time 1 hour 36 minutes
Course Main Course
Cuisine American
Servings 4 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
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