Roughly mash the lentils with a fork.
Mix the lentils, veggies, and meat with your hands in a large bowl. If you're going to grill the burgers, add an egg to keep them from crumbling.
Add salt and pepper to mixture. Form into 8 patties.
Grill the patties either on a barbecue or on the stovetop in a skillet over medium-high heat. Sear until dark brown on one side, then flip them and do the same on the other side.
Serve on toasted buns with your favorite condiments and fresh vegetables, like lettuce, tomato, and onion slices