3. Add the Cheese:
Once the sauce has thickened, reduce the heat to low and slowly add the cheddar cheese and mozzarella cheese, stirring until completely melted and smooth.
4. Season the Dip:
Stir in the garlic powder, onion powder, and mustard powder (if using). Add salt and pepper to taste.
If you like a bit of heat, sprinkle in a pinch of cayenne pepper.
5. Serve:
Remove the cheese dip from the heat and serve immediately alongside warm, freshly baked pretzels. You can also transfer it to a small serving bowl if you’d like.