Preheat oven to 175°C/350°F.
Beat the eggs in a bowl until stiff peaks form.
Gently melt the butter in a skillet or frying pan and fry the bacon until crispy. Add the tomatoes and cook for 2 minutes.
Pour the egg batter into the skillet so that it covers the base of the pan evenly. Cook on a medium heat for two minutes, then bake in the oven for 15 minutes.
Remove the frittata gently from the skillet, loosening with a spatula. Serve garnished with a fresh salad.