French Onion Patty Melt

Name: French Onion Patty Melt
Prep time: 30 min
Cook time: 1 h
Total time: 1 h 30 min
Cuisine: American
Ingredients: 2 lbs Ground Beef (80/20); 12-14 sliced Swiss Cheese; 1.5 cups Gruyere Cheese; 1.5 tbsp Kosher Salt; 1.5 tbsp Black Pepper; 1.5 tbsp Garlic Powder; 2 Yellow Onions (thinly sliced); 2 tbsp Brown Sugar; 1 tsp Kosher Salt; 1 tsp Black Pepper; ½ tsp Garlic Powder; 2 tbsp Ketchup; 2 tbsp Yellow Mustard; 2 tbsp Mayonnaise; 1 tbsp Pickled Relish; 1.5 tsp Hot Sauce; 6-8 slices Thick Cut Bread; French Fries (for serving); Pickles (for serving)