Serves 10 or more.
1 1-lb box of Velveeta, cut into 1-inch cubes
1 14-oz can Ro*Tel
Place Velveeta cubes in a 2-quart or larger microwave-safe glass bowl, and stir in the entire can of Ro*Tel. Cover the bowl with plastic wrap, leaving a small edge open to allow steam to escape. Cook on HIGH for 3 minutes. Stir, and cook for an additional 2 minutes. Stir again.
Leftover queso will solidify, and can be re-melted in the microwave.
To make on the stovetop, place Velveeta and Ro*Tel in a heavy sauce pan. Cook over low heat for 5 minutes, stirring frequently, until everything melts together.