Instructions

  1. Cook bacon until crisp.
  2. Drain on paper towels; reserve 3 tblsps drippings for dressing.
  3. Crumble bacon.
  4. Combine mayonnaise, onion, oil, vinegar, sugar and mustard with reserved drippings.
  5. (can be prepared 2 days ahead. Bring to room temperature before continuing.) Combine spinach, mushrooms and eggs in large bowl.
  6. Toss with dressing.
  7. Sprinkle with bacon and Parmesan.