Preheat the oven to 400ºF.

Melt butter in a large heavy based saucepan over a medium heat. Add the flour and stir to combined, cook for 2 minutes. Gradually add the milk and cream, whisking as you go, until a smooth sauce forms. Cook for 8-10 minutes, stirring continuously until sauce has thickened. Add the lemon zest, mild cheddar, 1oz of the parmesan cheese, cracked pepper and sea salt and stir until combined. Remove from heat.

Meanwhile, bring a large pot of salted water to the boil. Cook the rigatoni for 6-9 minutes or until al dente.

In a large casserole dish, combine the roux, peas, chives and pasta.

Break the Regal salmon into generous chunks and discard of the skin. Add the salmon to the casserole dish and gently fold through.

In a food processor, blitz sourdough into a rough crumb. In a bowl, toss together the crumbs, olive oil and minced garlic. Scatter over pasta bake

Top pasta bake with remaining parmesan cheese and sourdough crumbs and bake for 20-25 minutes until golden brown.