Wash and drain the iceberg lettuce, pat dry, and cut up fine with a French knife. Wash celery; scraping off the strings, and cut into small pieces. Wash, core and chop the green peppers. Finely chop the sweet onion or cut it into very thin rings, whichever you prefer.
In your best, large glass bowl, layer the iceberg lettuce, celery, green peppers, sweet onion and frozen peas, saving half the lettuce as the top layer.
Mix sour cream and mayonnaise together and spread over salad; do not stir in! Sprinkle sugar on top, then sprinkle cheddar cheese over all.
Cover bowl with plastic wrap. Refrigerate for 24 hours or 8 hours at the least. This is a party favorite, for it is totally ready a whole day ahead. It emerges cold and crisp to a degree. Being almost salt free (salt would make the greens weep), it is especially good with ham, but I use it with any and every meat. Excellent with boiled lobster, and a blessed switch from coleslaw.
Although I am inclined to downgrade iceberg lettuce, it has its place, and this is an extra-special recipe. One may use romaine lettuce, but then it is not the traditional 7 layered salad. I have also used extra layers of mushrooms and cooked, chopped bacon bits at the top.