Steps:

• Preheat the oven to 200C/180C Fan/Gas 6 and grease a 35x20cm/14x8in ovenproof dish..
• Melt the butter in a large saucepan over a low heat. Stir in the plain flour and cook for 1 minute. Add the mustard, take the pan off the heat and gradually whisk in the milk and cream. Add the bay leaf.
• Put the pan back over the heat, stirring constantly, until it boils and thickens. Take the pan off the heat again, remove the bay leaf and add the cheddar. Stir until the cheese has melted. Season with lots of black pepper and some nutmeg.
• Bring a large pan of salted water to the boil and stir in the macaroni. Cook for 10 minutes, or until al dente, drain well and add to the sauce.
• Fry the bacon in a frying pan until crisp. Stir into the macaroni cheese and pour the mixture into the ovenproof dish.
• Mix the breadcrumbs with the Parmesan and scatter over the top. Bake for 25–30 minutes, or until golden-brown and bubbling. Serve immediately.

Steps:

• Bring a large pot of water to a boil. Salt water and cook pasta to a chewy al dente, about 8 minutes.
• In a nonstick skillet, brown and crumble the sausage. Drain cooked crumbles on paper towel lined plate. Return pan to heat and add extra-virgin olive oil, butter, garlic and mushrooms. Season liberally with salt and pepper. Saute 3 to 5 minutes, until mushrooms are lightly golden.
• Preheat broiler to high.
• To mushrooms, add flour and stir, cooking 2 minutes. Whisk in stock, then stir in cream. Bring cream to a bubble, then stir in 2 cups of 4 cheese blend. When cheese has melted into sauce, add tomatoes. When sauce comes to a bubble, remove from heat and adjust seasonings, adding hot sauce if desired.
• Combine cheese sauce with sausage and pasta, transfer to flameproof baking dish, casserole or flameproof serving platter. Sprinkle remaining 1/2 cup of 4 cheese blend and the grated Parmesan over the top and brown under hot broiler.