My mother-in-law used to make this every summer and I could not get enough of it.
1 (16 ounce) package frozen peas, thawed
1 onion, finely chopped
2 hard-cooked eggs, chopped
½ cup mayonnaise
salt and ground black pepper to taste
Combine peas, onion, hard-cooked eggs, and mayonnaise in a large bowl. Stir well to combine. Season with salt and pepper. Chill for one hour before serving.