A main filling gives the sandwich identity, but quantity alone does not create quality. Tenderness, seasoning, temperature and cut size matter more than height.
Sliced deli meats
Fold thin slices loosely so they do not form a dense slab. Taste before adding salt; cured meats may already be salty. Pair rich meats with mustard, vinegar-dressed vegetables or pickles. Keep deli meat refrigerated and follow current food-safety guidance, especially for people at higher risk from Listeria.
Cooked whole meats
Slice across the grain and keep pieces thin enough to bite cleanly. Warm meat can wilt lettuce and melt spreads, so decide whether the sandwich is meant to be hot or cold. For leftovers, store meat separately from bread and assemble close to serving.
Chicken, tuna and egg salads
These fillings need enough binder to hold together but not so much that they squeeze out. Chop ingredients to a consistent size. Add crisp elements—celery, pickle, scallion or cabbage—shortly before serving. Keep them cold and do not treat mayonnaise as the only safety concern; the cooked protein itself is perishable.
Beans, chickpeas and lentils
Mash only part of the mixture so it retains texture. Season more assertively than you might season meat: salt, acid, herbs, spices and roasted vegetables help create depth. A thick bean spread can also act as a moisture barrier.
Roasted and grilled vegetables
Cool them before placing them on cold bread. Drain excess oil and cut long pieces into biteable lengths. Combine soft vegetables with something crisp or pickled so the sandwich does not feel uniformly soft.
Eggs
Fried eggs add richness and moisture; set the yolk to the degree appropriate for the eater and context. Scrambled eggs should be soft but not wet enough to soak the bread. Hard-cooked eggs work in slices or salads and should remain refrigerated until use.