I thought I'd find a dandy recipe for you in the Cheese Lover's Cookbook and Guide. It surprised me greatly to find 2 out of 3 recipes based on Velveeta (processed cheese). I don't actually object to Velveeta - it really makes a pretty decent nacho cheese dip in my opinion. But not everyone shares that opinion.
The book had one recipe that might suit. As with the recipe you found, it has cornstarch in it.
1 small onion, unpeeled and quartered
3 cloves garlic,...