Mince garlic. Heat oil over medium heat. Add garlic and red pepper flakes. Reduce heat to med-low and cook until garlic is golden (about 3-4 minutes). You can remove the garlic at this point, if you like.
Add the anchovies and stir into the oil. Cook over the med-low heat about 3-4 minutes or until anchovies resemble a paste. Reduce heat to low. Add the tomatoes. At this point, you can either just heat through (about 3-4 minutes) or you can leave to simmer about 20 minutes. The extra time will let the flavors simmer together.
Add cheese just before serving. This can be made a day in advance and it can be frozen.