The MAS Burger - Sutter Home Family Vineyards

Ingredients

• 1-2 tablespoons olive oil
• 1/2 red onion, chopped
• 1/2 lb. sliced mushrooms
• salt
• sugar
• pepper
• 1 lb. ground beef
• 1 tblp. fresh thyme, chopped
• 1 tblsp. fresh parsley, chopped
• 1 egg, beaten
• 1/2 cup fresh bread crumbs
• 1/4 lb. swiss cheese, cut into small pieces
• 4 Brioche buns
• 1/2 cup creamy dijon mustard
• 2-3 tblsp heavy cream
• red leaf lettuce