Baked mac and cheese with a sauce, not a packet
The sauce is a roux. 45 g of butter and 30 g of flour, cooked for a full minute so it does not taste raw, then milk whisked in slowly. If you dump the milk in at once, the flour clumps and you spend the rest of the recipe chasing them. A whisk and a slow pour fix it.
Cook the pasta one minute short. It finishes in the oven, and fully cooked elbows turn to mush under a blanket of sauce. Salt the pasta water. The cheese cannot season pasta that was boiled in plain water.
Cheese off the boil
Sharp cheddar, grated yourself. Pre-grated cheese is coated so it does not stick in the bag, and that coating makes the sauce grainy. Melt it off the heat. If the sauce is still bubbling when the cheese goes in, the fat splits out and you get grease on top of a stringy mess. 300 g looks like a lot. It is the right amount for 300 g of dry pasta.
80 g of heavy cream rounds the sauce. Double cream does the same job. The heavy cream chart puts a cup at 238 g, so 80 g is about 1/3 cup. Out of cream, leave it out rather than inventing a second dairy. The milk is already there. If you are out of milk entirely, the milk conversion and the butter chart are the numbers to scale from. The flour is 30 g, about 4 level tablespoons, on the flour chart.
The bake
180°C, 18 to 22 minutes. You want bubbling edges and a few gold spots, not a dark crust that has to be sawed. A broiler for the last 2 minutes is enough if the top is still pale. Rest 5 minutes before you scoop it, or the sauce runs off the pasta like soup.
It keeps three days. Reheat with a splash of milk over low heat, or covered in a 160°C oven. A microwave pile dries the edges and leaves the middle cold.
