Wash Lentils: Wash lentils in a bowl with cold water. Drain and repeat 4 to 5 times until water is noticeably clearer than in the beginning.
Cook Lentils: Cook lentils in a pot using a 2.5-3:1 water-to-lentil ratio for 10 minutes or until soft. Try not to overcook the lentils but don't stress if it happens. Drain excess water.
1 heaping cup dried red lentils
Sautee Onion: While your lentils are cooking away, chop up an onion and sauté it in oil for 7 to 10 minutes until it's soft and translucent.
1 onion, 3 tablespoons oil
Remove Water: Drain cooked lentils using a fine mesh strainer, remove excess water using a spoon, and stir in the salt and pepper.
¼ teaspoon salt, ¼ teaspoon pepper
Combine: Combine the cooked lentils and sauteed onion, taste the prepared filling, and add more salt or pepper if needed.
Cool: Let the filling cool for 20 minutes so any extra water can evaporated before using.