Wash the sweet pumpkin thoroughly, peel it, and cut into appropriate pieces.
Cook the sweet pumpkin using a microwave or steamer.
Place the cooked sweet pumpkin into a bowl and mash it.
Mix the mashed sweet pumpkin with mayonnaise, salt, pepper, and nuts.
Place the sweet pumpkin salad on sandwich bread.
Add lettuce or cheese if desired.
Cover with another slice of bread to complete the sandwich.