Head Cheese Sandwich

An assembly sandwich, so the only real variables are the head cheese and the bread. A few notes on both.

• What head cheese isNot cheese at all: a set terrine of meat from a simmered pig's head (sometimes trotters and tongue), suspended in its own gelatin. Delis and European butchers still carry it, often as souse, brawn, sülze or fromage de tête. Souse is the vinegar-soured version and will sharpen the sandwich considerably.
• Cutting itHead cheese is soft and the gelatin tears if it warms. Keep it cold, straight from the refrigerator, and use a thin sharp knife. The recipe simply says to cut the slices diagonally; on a narrow loaf that does give you longer slices, though the book does not say why it asks for it.
• The lettuceDipping the leaf in mayonnaise rather than spreading the bread may help keep the crumb dry, which matters when the filling is gelatinous, though the recipe gives no reason and the bread is buttered as well. Use a firm inner leaf of iceberg or romaine; soft butter lettuce collapses under the weight.
• Bread"Thin slices of white bread" points to a fine-crumbed sandwich loaf, cut thin. A standard supermarket slice is close enough; a crusty artisan loaf is not what the book has in mind.
• MayonnaiseMayonnaise in this period was generally made at home with raw yolk, and was often looser and sharper than the jarred kind. Commercial mayonnaise works directly; if you want more tang, thin it with a few drops of lemon juice or cider vinegar.
• The pickleA garnish here, not an ingredient, but it earns its place — the fat and gelatin need acid. A dill spear or sour gherkin alongside, or sliced into the sandwich if you prefer.
• Yield and servingOne sandwich per set of instructions. Cut in two on the diagonal and serve cold; it will not hold well once assembled, as the mayonnaise soaks into the bread.