Ingredients:

• 3 1/2 pounds chuck roast, cut into 1-inch pieces
• Kosher salt and freshly ground black pepper
• 4 tablespoons butter, divided
• 3 medium yellow onions, sliced 1/4 inch thick (about 8 cups)
• 3 tablespoons all-purpose flour
• 1 1/2 cups chicken or beef broth
• 1 1/2 cups (12 ounces) Belgian beer
• 4 sprigs fresh thyme
• 2 bay leaves
• 1 tablespoon whole-grain mustard
• 1 tablespoon brown sugar