French Onion Dip Sandwiches (Slow Cooker)

Details

Ingredients

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