Cook the pasta in a large saucepan of salted boiling water following packet directions or until al dente. Drain. Refresh under cold running water. Drain well.
Preheat oven to 180°C Brush six 185ml (3/4 cup) non stick Texas muffin pans with oil to lightly grease. Combine the macaroni, corn, capsicum, carrot and cheddar in a large bowl. Spoon evenly among prepared pans.
Whisk together the egg and milk in a jug and pour over the macaroni mixture. Bake in oven for 20 - 23 minutes or until just set. Remove from oven. Set aside in the pan for 5 minutes before carefully turning onto a wire rack to cool.
These frittatas will keep for up to 3 days. Store in an airtight container and bring to room temerature before serving.