1. Cook pasta according to package directions, however cook 2 minutes less than time indicated, since we will finish the pasta in the oven. Drain pasta and return to original pot, reserving ½ cup of the cooked pasta water to use in the cheese sauce. Stir in 1 tablespoon of butter to the pasta to coat it until mixed.
Don’t dump the pasta water!
2. While pasta is cooking, make the sauce, and preheat oven to 450 degrees.
3. In a heavy bottomed saucepan, over medium heat, melt the butter, then vigorously whisk in the flour. Cook for a minute or two, just until the flour begins to give off an aromatic smell and darkens slightly. Whisk in the pasta water and 1 cup of the milk until the mixture is smooth, then add the other 2 cups of milk. Cook, whisking regularly, until sauce is the consistency of heavy cream, approximately 4-6 minutes. The sauce is perfect when it coats the back of a spoon. Reduce the heat slightly if sauce begins to bubble.
4. Stir in the lemon juice, salt (to taste), white pepper, red pepper flakes, and cayenne.
5. Add the 3 cups of gouda cheese, ½ cup of cheddar, and ½ cup of the mozzarella, then remove from heat. Continue stirring to incorporate the cheeses, noting not all of the cheeses need to be melted because the macaroni and cheese will be heated in the oven. Pour the sauce into the cooked pasta and stir well.
6. Transfer mixture to a greased oven-safe casserole dish. Scatter the remaining 1½ cups grated sharp cheddar and 1½ cups grated mozzarella cheese on top of the pasta. Cook for 20-25 minutes, until lightly browned and bubbly. I like the top to be very brown, so I finish the dish by setting the oven on broil and cooking for an additional minute or two, watching it carefully so it doesn’t burn.
7. Remove from oven, place on wire rack to let rest a few minutes, then serve.
