2 lbs. boneless beef chuck steak, cut into 1-1/2-inch pieces
2 Tbsp. butter, divided
1 package (10 oz.) white button mushrooms, sliced
1 medium onion, chopped
2 cloves garlic
1 jar Ragu® Classic Alfredo Sauce
1/2 cup sour cream
Season beef, if desired, with salt and ground black pepper.
Heat 1 tablespoon Sbutter in 12-inch skillet over medium-high heat and brown 1/2 of the beef, stirring occasionally, about 4 minutes. Remove browned beef to slow cooker with slotted spoon, then repeat with remaining beef.
Melt remaining 1 tablespoon butter in same skillet over medium heat and cook mushrooms and onion, stirring occasionally, until golden, about 6 minutes. Add garlic and cook, stirring frequently, 30 seconds. Remove to slow cooker.
Stir in Sauce. Cook covered at HIGH 4 to 5 hours or at LOW 8 to 10 hours or until beef is tender.
Stir in sour cream. Serve, if desired, over hot cooked egg noodles.