Mix the flour with the cold butter cut into small pieces. Add 1 egg and 1 pinch of salt. Knead to a smooth dough for about 30 minutes. Wrap in plastic and chill.
Rinse the tomatoes and coarsely chop. Cut the mozzarella into small cubes.
Mix the remaining eggs with the cream, Gruyere, and herbs. Season with salt and pepper. Stir in the tomatoes and mozzarella.
Form the dough into 12 equal-sized balls. Roll out onto a lightly floured surface about 10 cm (approximately 4 inches). Grease the muffin pans and line with the balls of dough. Spread the tomato, egg mixture on top and bake in a preheated oven at 220°C (approximately 425°F) for about 30 minutes. Bake and remove from the pan. Serve while warm.