Step 1: Prepare the ingredients. Finely chop the iceberg lettuce, celery, and red onion. Thaw the frozen peas. Cook bacon until crisp, then crumble. If using, hard-boil and chop the eggs. Shred the cheddar cheese.
Step 2: Make the dressing. In a medium bowl, whisk together the mayonnaise, granulated sugar, and apple cider vinegar (if using). Season with a pinch of salt and black pepper. Taste and adjust sweetness or tang as desired. Cover and refrigerate until ready to use.
Step 3: Layer the salad. In a large, clear glass trifle bowl (or deep salad bowl), start with the first layer: spread the chopped iceberg lettuce evenly across the bottom.
Step 4: Add the second layer: sprinkle the thawed peas over the lettuce.
Step 5: Add the third layer: distribute the chopped celery evenly over the peas.
Step 6: Add the fourth layer: sprinkle the chopped red onion over the celery.
Step 7: Add the fifth layer: evenly scatter the crumbled bacon over the red onion.
Step 8: Add the sixth layer: if using, gently place the chopped hard-boiled eggs over the bacon.
Step 9: Add the seventh layer: generously sprinkle the shredded cheddar cheese over the entire salad. Ensure it covers the other layers well.
Step 10: Finish with the dressing. Carefully spread the prepared mayonnaise dressing over the top layer of cheese, ensuring it completely seals the top of the salad. Do not mix the layers.
Step 11: Chill and serve. Cover the bowl tightly with plastic wrap and refrigerate for at least 4-6 hours, or preferably overnight, to allow the flavors to meld. When ready to serve, simply bring it to the table and scoop down to get all seven glorious layers of the Midwest Seven Layer Salad on each plate. Enjoy this timeless potluck classic!