Gather and prepare all ingredients. Preheat the oven to 400°F.
Bring the water to a simmer in a medium pot. Once it’s simmering, add the lentils. Let the pot return to a simmer, then place a tilted lid on top. Allow the lentils to simmer for about 20 minutes. After 20 minutes, taste the lentils to test the texture. They should be tender but not mushy. Drain the lentils in a colander and rinse with cold water to cool.
Place 1¼ cups (about 240g) of the cooked lentils, garlic, tomato paste, salt, pepper, paprika, and cumin in the food processor. Blend until the ingredients are just combined and form a paste-like consistency, scraping down the sides as needed. Then place it into a large bowl.
Next, add the remaining cooked lentils, carrots, onions, and flour to the bowl. Fold to combine.
Divide the lentil mixture into 4 evenly sized patties, about ½-inch thick. Make sure to press them together firmly so they hold their shape***. Arrange the patties on a parchment-lined sheet tray coated with nonstick spray, then lightly spray the tops of the burgers as well.
Bake for about 15 minutes, then gently flip the patties over, and spray again with nonstick spray. Bake for about 15 more minutes.
Place the lentil burgers on buns with your favorite toppings and enjoy.
*Brown lentils give me the most reliable texture for these patties. Green and red lentils also work, but follow the package cooking time. Red lentils soften and break down easily, so expect to add extra flour before shaping. Short on time? You can use canned lentils instead! I recommend draining them, rinsing them, and patting them dry. You’ll need about 3½-3¾ cups drained canned lentils. Adjust flour as needed to make sure the patties hold together.**Flour absorbs moisture and keeps this recipe egg-free, but breadcrumbs, rolled oats, or ground oats will also work. These aren’t exact one-for-one substitutions, so adjust the amount until the mixture stays formed when pressed. For gluten-free burgers, use certified gluten-free oats, flour, or breadcrumbs.***I firmly pressed the mixture together to hold and form the patties. If the mixture seems too dry, add a little water or oil. If the mixture seems too wet, add a little flour to help absorb the moisture.Skillet directions: You can cook these burgers in a skillet in hot oil over medium heat for 5-6 minutes on each side. I do, however, recommend refrigerating them for about 30 minutes before cooking because they tend to fall apart in the skillet since you’re handling them more!Make them a freezer meal! Freeze the shaped unbaked patties OR fully cooled cooked patties for 2-3 months, placing parchment paper between them. Thaw overnight in the refrigerator, then bake unbaked patties according to the recipe or reheat cooked patties in a 350°F oven until hot throughout.