French Onion Dip Sandwiches (Slow Cooker)

Ingredients (17)

• + 5 tablespoons olive oil, divided add to pantry
• + 2 large onions, thinly sliced add to pantry
• + 3 tablespoons butter, divided add to pantry
• + 1 teaspoon white sugar add to pantry
• + ½ teaspoon salt add to pantry
• ✓ 3 cloves garlic, minced
• + 9 tablespoons water add to pantry
• + ¼ cup dry vermouth add to pantry
• + 2 ½ cups beef stock add to pantry
• + 1 tablespoon Worcestershire sauce add to pantry
• + 1 tablespoon soy sauce add to pantry
• ✓ 1 teaspoon fresh thyme
• + 1 bay leaf add to pantry
• + ¼ teaspoon ground black pepper add to pantry
• + 3 pounds rump roast add to pantry
• + 8 French rolls, split add to pantry
• + 1 (6 ounce) package grated Gruyere cheese add to pantry