Chop bacon and cook on medium heat until browned. Add in chopped onion and cook until tender. Remove from skillet. Boil 4 cups water and add grits.
Cook about 5 minutes on medium, add in half and half, butter, and shredded cheese. Remove from heat and cover.
Add shrimp to skillet used to cook bacon and onions. Cook 3 minutes on one side and then turn. Add bacon and onion mixture back to the skillet and add in minced garlic. Cook 3 additional minutes.