Cut tops from the tomatoes.
Scoop out a hollow in the middle of each tomato large enough to hold the egg.
Place 1 tsp (5 mL) of butter in each tomato hollow.
Break an egg into each hollow.
Place tomatoes on a baking sheet or 8 or 9 in. (20 or 23 cm) pie pan.
Bake at 350°F (175°C) for 15 to 18 minutes or until eggs are firm and tomato is cooked.