Gently peel back outer leaves of cabbage. Slice 1/2 in. from bottom of cabbage so it sits flat. Cut a 3-in. circle in the top of the cabbage; hollow out a third of the cabbage to form a bowl (save removed cabbage for another use).
In a large bowl, combine the spinach, sour cream, mayonnaise, onions, parsley, lemon juice and dill. Spoon into cabbage bowl just before serving. Serve with vegetables. Yield: 3 cups.