Select saute setting on a 6-qt. electric pressure cooker and adjust for medium heat. Add half the ground beef, salt and pepper. Cook and stir until no longer pink, 6-8 minutes; crumble beef. Remove meat; drain any liquid from pressure cooker. Repeat with remaining ground beef, salt and pepper., Add butter, mushrooms and onions to pressure cooker; saute until onions are tender and mushrooms have released their liquid and are beginning to brown, 6-8 minutes. Add garlic; cook 1 minute longer. Return meat to cooker; add tomato paste and consomme. Press cancel., Lock lid; close pressure-release valve. Adjust to pressure-cook on high for 5 minutes. Quick-release pressure., Select saute setting and adjust for low heat. In a small bowl, whisk together flour and water. Pour over meat mixture; stir to combine. Cook and stir until thickened. Stir in sour cream; cook until heated through. If desired, serve with noodles and minced parsley.