Roll out each slice of bread until it’s very thin with a rolling pin. Lightly spread one side of each slice with the butter.
Place the bread slices, buttered-side down, to line the muffin tray, pressing down to fit tightly. Bake for 15 minutes or until crisp and golden.
Break the eggs into a large bowl. Add the milk, salt, pepper, chicken and half the cheese. Spoon the mixture into the bread cases and sprinkle with rest of the cheese and chopped parsley.