Preheat oven to 375°F. Slice off the tops of tomatoes. Carefully scoop out the pulp. Place tomatoes in a show baking pan. Crack an egg into each tomato cup. Add ¼ tablespoon butter, sprinkle with tarragon and season with salt and pepper.
Bake for 25 to 30 minutes. Remove and serve immediately with toast.
If you prefer your egg yolks to be runny, bake for 20 to 25 minutes.