Heat a medium skillet over low-medium heat, and add the cubed Velveeta, butter, salt, garlic powder, and onion powder. Stir until smooth then remove from heat. Don't leave it unattended! The sauce burns very easily, so stir often.
16 ounces Velveeta, ½ cup unsalted butter, 1 teaspoon salt, ½ teaspoon garlic powder, ¼ teaspoon onion powder, ¼ teaspoon ground black pepper