Preheat a broiler / grill.

Microwave the gammon for 1½ minutes.

Microwave the onion for 2 minutes and whilst it cooks cut the gammon into cubes.

Put a small pan on medium to high heat. Add the gammon and onions together with the crème fraîche, mustard and peas. Season with pepper liberally and leave to gently simmer.

Microwave the potato for 3 minutes in a lidded container with a little water.

Transfer the ham and onion mix to an ovenproof dish and spread the potato over the top. Season the potato with salt and pepper. Spray with Spray2Cook and put the dish under the broiler / grill until the potato browns and then serve.