Fill a large pot with water. Add a pinch of salt to it. Bring the water to a rolling boil. Add the macaroni noodles to the pot. Cook them until they are slightly firm. This is called "al dente" style. Do not overcook the pasta now. It will cook more in the oven. Drain the water using your colander. Set the pasta aside for later.

Place a saucepan over medium heat. Add the butter and let it melt. Sprinkle the flour into the melted butter. Whisk them together for one minute. It should look like a thick paste. This helps thicken your cheese sauce later. Do not let the flour turn brown. Keep the heat at a medium level.

Slowly pour in the milk and cream. Keep whisking while you pour the liquid. This prevents lumps from forming in sauce. Cook the mixture for five minutes. It will start to get thick and bubbly. It should coat the back of a spoon. This is the base for your cheese.

Turn the heat down to very low. Add the cheddar and Monterey Jack cheese. Add the Fontina and Parmesan cheese too. Stir until the cheese is totally melted. The sauce should look very smooth now. Add your salt, pepper, and mustard powder. Taste it to see if it needs salt.

Pour the cooked macaroni into a big bowl. Pour the warm cheese sauce over it. Stir gently to coat every single noodle. The mixture should look very wet and creamy. The noodles will soak up some sauce later.

Grease your baking dish with some butter. Pour the mac and cheese into the dish. Spread it out evenly with a spoon. You can add extra cheese on top. Put it in a 350-degree oven. Bake for about 20 to 25 minutes. The top should be golden and bubbly.