Carbonnade Beef and Beer Stew

Name: Carbonnade Beef and Beer Stew
Prep time: 15 min
Cook time: 3 h 30 min
Total time: 3 h 45 min
Cuisine: European, Mediterranean, French
Ingredients: 3 1/2 lbs chuck roast, cut into 1-inch pieces; Salt and freshly ground black pepper; 4 Tbsp butter, divided 2 Tbsp and 2 Tbsp; 3 medium yellow onions sliced about 1/4 inch thick (about 8 cups); 3 Tbsp all-purpose flour; 1 1/2 cups chicken or beef broth; 1 1/2 cups (12 oz bottle) Belgian beer; 4 sprigs fresh thyme; 2 bay leaves; 1 Tbsp whole grain mustard; 1 Tbsp brown sugar