Trim all excess fat from beef. Shake cubes, part at a time, with flour in a plastic bag to coat well. Combine tomato juice and instant beef broth in a small saucepan; heat just to boiling; remove from heat.
Combine parlsey, garlic, salt and pepper in a cup. Layer vegetables and meat into a slow cooker this way: Half of each of potatoes, onions and beef, sprinkling each layer lightly with seasoning mixture. Repeat with remaiing potatoes, onions, beef and seasonings.
Cut each squash half into 6 slices; pare; arrange on top. Pour hot tomato juice mixture over; dot with butter or margarine, cover.
Cook on low for 8 hours or on high for 4 hours, or until meat and vegetables are tender.