PREPARATION:
1st Step
You need to begin by heating the oven to 375 degrees Fahrenheit (190 degrees Celsius). Prepare a 9×13-inch baking dish or another oven-safe container of comparable dimensions and set it aside.
2nd Step
Bring to a simmer a large kettle of salted water. Add elbow macaroni (or your preferred pasta) and prepare it according to the instructions on the package until it is just undercooked. The pasta will continue to simmer in the oven, so it should not be overcooked at this point. Drain and put aside the pasta.
3rd Step
In a saucepan of medium size, soften the butter over medium heat. After the butter has completely dissolved, stir in the all-purpose flour to create a roux. Cook the roux for one to two minutes, until it turns golden brown.
4th Step
Pour the whole milk and heavy cream gradually while whisking continuously to prevent clots. Continue stirring for 5 to 7 minutes, or until the mixture thickens and becomes homogeneous.
5th Step
Reduce the heat to medium and stir in the shredded cheeses, reserving approximately 1/2 cup for the garnish. Stir the cheese into the sauce until it has melted completely and the sauce has thickened and become velvety.