Leftover Pot Roast Patty Melts

Directions

1. Re-heat the pot roast in the microwave. Butter one side of all 8 slices of bread.
2. 
   
3. Melt 3 tablespoons of butter in a large skillet. Add onions and cook over medium heat, stirring frequently, until onions are soft and golden brown
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5. Season with salt and pepper and remove from heat.
7. Combine the sauce ingredients in a medium bowl.
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9. Heat a griddle over medium-high heat. Spread a layer of the sauce on the unbuttered side of 4 slices of bread. Top with a piece of cheddar cheese.
10. 
    
11. Top each slice of cheddar with about 1/2 cup of pot roast, a generous portion of onions, and the slice of Provolone cheese. Top with the remaining slice of bread, buttered side out.
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13. Grill, flipping once, until both sides are browned and crispy.
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15. Serve patty melts with the remaining sauce, for dipping.