Preheat the oven to 350°F. Spray a baking dish with nonstick spray.
In a medium saucepan, heat the olive oil over medium heat. Add 3 cloves garlic, 1/2 teaspoon salt, and 3/4 teaspoon chili powder. Cook 1 minute, or until fragrant.
Pour in the beans (I usually leave 1 can with juice and drain the other) and water. Cover and cook 5 minutes.
Mash beans. Remove the lid and reduce the heat to low. Use a potato masher or fork to mash the beans until you reach your desired consistency. You can also use an immersion blender if you prefer a smoother consistency. Bring to a light simmer for 2 minutes. Add a splash more water if they become too thick or simmer longer to allow more moisture to evaporate if needed. Remove from heat and stir in optional add-ins, if using. Season to taste.
Assemble burritos. Spread about 1/3 cup of the beans down the center of a tortilla. Add 1 to 2 Tablespoons of cheese over the top. Fold the bottom edge over the filling and then fold in the sides and roll up.
Place in baking dish and bake 10 minutes. Serve while warm. Add desired toppings.
Notes
Storage: Store burritos in a covered container for up to 5 days or freeze for up to 3 months.To reheat: Thaw them in the fridge overnight. You can use the microwave, the oven, or the air fryer to warm them through.