Slow Cooker Hearty Porter Beef Stroganoff

Ingredients

• 4 tablespoons unsalted butter
• 16 ounces porter beer
• 1 cup sour cream
• 1 teaspoon salt
• 8 ounces white mushrooms, sliced
• 1/2 teaspoon black pepper
• 1 large white onion, diced
• 2 pounds beef sirloin, whole piece with excess fat trimmed
• 1 bag (16 ounces) egg noodles, cooked per package instructions
• 1 can (10.5 ounces) Cream of Mushroom Soup