There isn't a single dish I have made more than Baked Macaroni and Cheese. When I was a child, I received the Charlie Brown Cook Book one Christmas and it's the first recipe I made from that book and have made variations of it since.
This recipe for the most part comes from a Martha Stewart Living issue, her 10 Year Anniversary magazine. I believe I cut the cheese in half. A good Macaroni and Cheese begins with a bechemel, a white sauce. It begins with equal parts butter and flour. Then it goes from there.
In a large pot of salted water, cook 12 oz Pasta and drain. A pasta shape that has a hole works best. Cook pasta so it is under done, otherwise the pasta will be mushy once it bakes.
In a saucepan over medium heat, melt 1/2 Stick UnSalted Butter. Add 1/4 C Flour and stir with a whire whip continually for 3 minutes, DO NOT LET BROWN. Add 4 C Whole Milk 1/2 C at a time, stirring all the while, 1/4 C Heavy Cream OR 1/2 & 1/2. This should take about 8 minutes. Turn off heat. Season with S&P.
Add 8 oz Grated White Cheddar Cheese (reserve 1/2 cup cheese for topping) and 5 oz Parmesan Cheese (reserve 1/4 C for the topping. Add pasta to cheese mixture. Place into buttered caserole dish.