Easy, and easily beats the blue stuff. Took me just a few minutes longer, and one more pan than the convenience version. I started with the recipe here, but wound up with a significant enough deviation that I want to post it here so I’ll remember it.

For two people:

2 cups pasta (shells FTW)

1.5 Tbs. butter

1.5 Tbs. all-purpose flour
0.25 Tsp. kosher salt
A pinch of:
- cayenne
- freshly ground black pepper
- paprika

0.75 C skim milk
between 0.5 and 1 cup assorted cheese
My mix was approximately:
- 80% sharp cheddar
- 10% plain Chavrie (very chèvre-like goat’s milk cheese from PA)
- 10% feta

Melt butter in a small saucepan and remove it from the heat to stir in the flour and seasonings. Gradually add the milk, stirring until well mixed; the mixture will seem quite thin at this point. Return to the heat and cook over low to medium-low heat, stirring frequently. Once the sauce has thickened and seems smooth, cook for about 5 more minutes. Add the cheeses and stir until everything is smooth.

On my stove with medium shells, the time to start the water boiling for the pasta was when the milk/flour/spice mixture returned to the heat.