Preheat oven to 375 degrees. Place an cast iron skillet in the oven to preheat (or other oven proof skillet or baking sheet.)
Pick over the lentils removing any debris or rocks. Add the lentils to a small saucepan and add 1 cup of water. Heat on medium until the lentils come to a boil. Cook for about 5 minutes or until the lentils or done. Drain the lentils reserving the cooking liquid. Set aside.
Place the garlic, parsley and cilantro in the bowl of a food processor. Process until well mixed and chopped.
Add the chickpeas, 1/2 the cooked lentils with some of the reserved cooking liquid, spices, and lemon juice to the processor. Blend until mixed but still somewhat chunky.
Remove the mixture to a large mixing bowl and add the remaining lentils, 2 tablespoons of the oat bran, and the red onion. Fold together using a rubber spatula until blended.
If the mixture seems dry add a little more of the reserved cooking liquid. If too wet add another tablespoon of the oat bran. In the end the mixture should be damp and hold together well, but not wet.
Add 1 or 2 tablespoons vegetable oil to the hot skillet and place the falafel burgers in the pan. Do not crowd the pan and cook them in two batches if needed. I used two skillets and had plenty of room.
Bake for 30 minutes, turning carefully after 15 minutes to ensure both sides are crispy.