1Add oil to skillet over medium-high heat. Add onion and garlic, stir for a few minutes until onion becomes translucent.
Add ground beef. Break up with spoon and continue to do so and stir until all meat is browned.
Add cumin, salt and pepper. Stir and cook for a few minutes, then taste for seasoning.
2Add refried beans, and mix to thoroughly combine. Let mixture cool for 10 minutes.
3Lay one tortilla on a flat surface and spoon 3-4 tablespoons of the mixture and spread over the tortilla. Leave a quarter inch of space around the edge.
Roll up the tortilla and place in a greased 9" x 13" baking dish. Repeat with remaining tortillas. Leave a little space between the rolls if you can. The number of rolls will depend on how much filling you use in each. (Leftover meat mixture can be refrigerated and is great for nachos.)
Pour enchilada sauce over the rolls and covering the rolls completely with sauce. Sprinkle on grated cheese and top with olives and/or onions, if desired.
Bake at 350F, uncovered, for 20-30 minutes. It's done when the cheese is melted and the sauce is bubbling around the sides.