Largely dice 5 slices of bacon and fry in a cast iron skillet. Once cooked, remove bacon from pan with slotted spoon. Pour out the bacon remaining in pain. Add 3 tablespoons of the bacon fat back into the skillet, along with butter or olive oil. Add Brussels cut side down. Once they are browned begin stirring the Brussels around. Add salt and pepper. Once they are cooked to your liking add in garlic. Toss around being careful not to burn garlic.