Sweet Potato Fry Burger with Cheesy Sautéed Onions

1. Saute´ onions in butter over medium-high heat, 15 minutes or until softened.

2. Slowly add ¼ of beer, let reduce down until almost evaporated.

3. Continue to add beer until gone or the onions have caramelized.

4. Stir in Gruyere cheese, cover pan and cook 2-3 minutes or until cheese has melted.

5. Place burgers on bottom bun, top with onion mixture and sweet potatoes.