Finely grate or chop the onion and garlic. Sauté them with 1 teaspoon of oregano and a splash of olive oil for 5-6 minutes. Add the sautéed mixture to the drained lentils, mustard, breadcrumbs, and a pinch of salt and pepper. Gently mix until everything is well combined.

Shape the mixture into burgers with your hands. First, form a ball and press it with your fist to compact the lentils, then flatten it with your other hand. Fry the burgers in a little olive oil for a couple of minutes on each side.

Assemble the burgers on buns with your favorite toppings!