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 1⁄2-inch rounds
  • 2 medium carrots, peeled and cut into 1⁄2-inch rounds
  • 1 tsp. grapeseed oil
  • 2 tsp. salt, divided
  • 1⁄2 tsp. ground black pepper, divided
  • 2 slices gluten-free bread, toasted
  • 1 cup canned lentils, drained and rinsed well
  • 1 large egg
  • 1 cup 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 1⁄4 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 to 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.