French Dip Sliders

Name: French Dip Sliders
Cuisine: European, American, Mediterranean, French
Ingredients: 3 tablespoons unsalted butter; 1 medium onion, thinly sliced; 2 teaspoon fresh thyme, minced; 1/4 teaspoon kosher salt; 1/4 teaspoon black pepper; 12 sweet rolls; 10 slices provolone cheese; 14 ounces sliced deli roast beef; 1/2 cup unsalted butter, melted; 1 & 1/2 tablespoons dried onion soup mix; 1 packet au jus gravy mix; 3 cups water; fresh chopped parsley for garnish, optional