Slow Cooker Black Forest Pot Roast

Ingredients (13)

• 3½ pounds boneless beef chuck roast
• 1 large onion,
• 1/4 cup water
• 4 whole dried shiitake mushrooms, stems removed
• 1/4 cup ketchup
• 1/4 cup dry red wine
• 2 tablespoons Dijon mustard
• 1 tablespoon Worcestershire sauce
• 1/2 teaspoon salt
• 1/8 teaspoon black pepper
• 1 medium garlic clove,
• 2 tablespoons cornstarch
• 3 tablespoons water