Patty Melts with Secret Sauce

Ingredients:
For the patty melts:
- 1 lb. Ground beef
- 6 Slices rye bread
- ½ tsp. Onion powder
- ½ tsp. Garlic powder
- Salt and pepper to taste
- 6 Slices cheddar cheese
- 6 Sliced provolone cheese
- 6 Tbsp. Butter, softened and unsalted