Final answer:
The subject of this question is Home Economics, and the answer is egg salad.
Step-by-step explanation:
The subject of this question is Home Economics. Martha Stewart's favorite recipe for this sandwich includes light mayo and uses 10 egg whites and only 2 egg yolks. The sandwich that matches this description is egg salad. Egg salad is typically made by mixing chopped hard-boiled eggs with mayonnaise, and the recipe that Martha Stewart prefers includes mostly egg whites and a smaller proportion of egg yolks.