Pre-heat the oven to 350F. Prepare the ingredients -- Fry the bacon until it's a little crispy. Fry the onion and set aside. Boil the potato until it's soft and then slice it. Lightly grease the 5 inch pie tins. Beat one egg and set aside in a bowl to brush the pastry. Alternatively, you can just brush the tops with milk. Have ready 1 or 2 eggs per pie. Cut 5 inch circles out of the store-bought pastry for the pie base and the pie top. Grate about 1/3 cup of cheddar cheese. Slice several cherry tomatoes.