-
1
Stir the macaroni, 1 cup of the milk and 1/4 teaspoon salt in a microwave-safe 4-quart bowl.
-
2
(It is important that you use a bowl large enough to prevent the milk from boiling over.)
-
3
Cover tightly with plastic wrap; cut a small slit in the center with the tip of a paring knife to vent excess steam.
-
4
Microwave on high (at 100 percent power) for 4 minutes in either an 1,100- or a 700-watt oven.
-
5
Uncover (be careful to avoid the hot steam) and stir.
-
6
Cover and microwave on high (at 100 percent power) until the macaroni is about two-thirds cooked, a little harder than al dente, 1 1/2 minutes in an 1,100-watt oven or 3 1/2 minutes in a 700-watt oven.
-
7
Add the remaining cup of milk, American cheese, Jack cheese, Parmesan, cream cheese and mustard.
-
8
Stir well, cover tightly and microwave on high (at 100 percent power) until all the cheeses have melted, 4 minutes in an 1,100-watt oven or 4 1/2 in a 700-watt oven.
-
9
Stir until thoroughly combined.
-
10
If there are still some pieces of unmelted cheese, microwave again, covered, in 30-second increments.
-
11
(The sauce will continue to thicken as it sits.)
-
12
If desired, transfer to a decorative dish for serving.
