Preheat oven to 375 degrees.
Boil a large pot with salted water over high heat.
Add the macaroni and cook for about 5 minutes.
Drain the macaroni and rinse with cold water. Reserve some of the water from the pasta in case you need it later. This is important. You want the pasta to cool so that it does not continue to cook. The pasta will cook again while baking in the oven. Over-cooked pasta results in a terrible texture.
Heat a sauce pan on medium heat. Add the butter and allow it to melt.
Once melted, add the flour and whisk.
This will create a slurry. Continue to whisk until the four is fully combined.
Add the milk and heavy whipping cream and stir.
Add half of the cheese and stir until the cheese is melted.
Add the seasonings and taste repeatedly. This step is important because you don't want bland mac and cheese.
Return the pasta to the large pot. Drizzle the liquid mixture over the pasta and stir until fully combined.
Spray a baking pan with cooking spray.
Begin to layer in the pasta. Start with the pasta, then add a layer of all of the shredded cheese and muenster chunks.
Add another layer of pasta, and then another layer of cheese.
Ensure there is adequate liquid throughout these steps (additional milk or reserved pasta water work well). This can be tricky. You do not want the dish to appear like soup, but you do not want it to be dry.
This step is important because without adequate liquid the dish will dry out while baking.
Bake for 20-30 minutes until the cheese has melted and is bubbly
Cool before serving.