1) Chop up the veggies for the migas as evenly as possible.
2) Dice up your corn tortillas into strips. Heat oil in a cast iron skillet over medium-high heat and fry corn strips until they are very cripsy. About 5-6 minutes should be good.
3) For refried beans, melt butter in a large skillet. Add onions and garlic over medium heat and cook until they are soft, about 3 minutes. Then add drained beans and a small amount of water. Use a fork or spatula to lightly mash the beans as they cook.
4) After your corn strips come out of the pan, pour out any extra oil. You only need a thin coat. Then add all the veggies and turn the heat to medium.
5) Cook the veggies until they are soft, about 4-5 minutes. Then add the corn strips back in and mix everything well.
6) In a separate bowl, whisk eggs with milk. Pour egg mixture over the veggies and corn strips.
7) Cook for a few minutes so the eggs start to firm up nicely, then add grated cheese.
8) Finish the migas in a 400 degree oven for 5 minutes or on the stovetop. Just heat until the eggs are firm and the cheese is melted.
9) Serve with beans and tortillas and plenty of hot sauce.