Hearty burgers get a healthy makeover with canned lentils. Spread on a tangy yogurt-mint sauce, and serve a zesty carrot salad on the side.
In a food processor fitted with the shredding disk, shred carrots. Transfer to a medium bowl; toss with 2 tablespoons lemon juice, 1 tablespoon oil, and half the scallions. Season with salt and pepper; set aside.
Wipe food processor clean, and fit with chopping blade. Process 1 bun until finely ground. Add lentils, egg, half the mint, 1 teaspoon salt, 3/4 teaspoon pepper, and remaining scallions. Pulse just until combined.
Dividing evenly, shape mixture into four 3 1/2-inch patties. In a large skillet, heat remaining 2 tablespoons oil over medium. Cook burgers until browned and firm, 4 to 5 minutes per side.
In a small bowl, combine yogurt, remaining mint, and remaining tablespoon lemon juice; season with salt and pepper. Place burgers on buns, and top with yogurt sauce and lettuce. Serve with carrot salad.
When combining the burger ingredients in the food processor, don't overprocess; you want some small chunks to remain to give the patties a nice texture.