1. Preheat the oven to 200C (fan 180C), 400F, Gas Mark 6.
2. Bring a large pan of salted water to the boil and cook the pasta for 10-12 minutes until al dente (or according to pack instructions). Drain well and return to the pan.
3. Add the milk, cream, cheddar, Parmesan, garlic and salt and pepper to the pasta and place on a medium heat to bring it to a simmer, stirring. Allow to simmer slightly for a few minutes to thicken before stirring in the ham. Transfer to a large baking dish or four individual ones. Dot the relish all over and then swirl in a little. Set aside.
4. Mix the breadcrumbs, butter, Parmesan and 2 tablespoons of chives together in a small bowl and scatter them evenly over the top of the pasta.
5. Bake for 10-15 minutes until the topping is golden and crunchy. Scatter over the remaining chives and serve at once with a crisp green salad.
Add other ingredients like cherry tomatoes, chopped spring onion and / or peppers to the mix before baking.