Preheat the oven to Gas Mark 4/180C
Butter a small loaf tin ( I find a silicone tin works really well) or a 6-hole muffin tin.
Break the eggs into a medium bowl. Add the milk or cream to the eggs. Whisk the eggs with a fork or metal whisk until it is light and fluffy.
Add your choice of cheese, herbs and vegetables to the mix and fold in lightly. Season lightly.
Pour the mixture into the loaf or muffin tin. Place the halved tomatoes on top.
Bake for approximately 40 minutes for the loaf or 20 minutes for the muffins until the frittata is golden-brown and set. Check that it is cooked in the middle by poking in a sharp knife. If it is still loose return the dish to the oven until set. Leave to cool a little before removing from the tin.You can eat it warm or cold.