You can’t put high-FODMAP mushrooms on top of these burgers, but a drizzle of black truffle oil before and after grilling provides a similar—more dramatic—earthy flavor.

Serves: 6Hands-on: 10 minutesTotal: 12 hours 50 minutesDifficulty: Easy

Serves: 6


  • 2 medium parsnips, peeled and cut into ½" rounds
  • 2 medium carrots, peeled and cut into ½" rounds
  • 1 tsp. grapeseed oil
  • 2 tsp. salt, divided
  • ½ tsp. freshly ground black pepper, divided
  • 2 slices gluten-free bread, toasted
  • 1 cup canned lentils, drained and rinsed well
  • 1 large egg
  • 1 cup freshly grated Parmesan cheese
  • 1 tsp. black truffle oil


  • Preheat oven to 400°F. Line a baking sheet with parchment paper.
  • In a large bowl, toss parsnips and carrots with grapeseed oil, 1 teaspoon salt, and ¼ teaspoon pepper. Spread on baking sheet and bake 30 minutes. Set aside to cool.
  • In a food processor, pulse toast to a crumb consistency. Transfer to a bowl.
  • Add roasted vegetables to food processor and pulse until there are no major lumps. Add remaining salt and pepper, toasted bread crumbs, lentils, egg, and cheese. Pulse to combine.
  • Transfer to a workspace and form 6 equal patty rounds.
  • Refrigerate patties 12–24 hours before grilling. Brush surface of burgers lightly with truffle oil. Grill patties 3–4 minutes on each side. Brush lightly with additional truffle oil before serving.