The ham and pimiento cheese is a Southern argument that the cheese should be a spread, not a slice, and the spread is what runs the sandwich. Pimiento cheese is grated sharp cheddar bound with mayonnaise and studded with chopped pimientos, a cool, tangy, slightly loose paste rather than a firm sliceable cheese. Lay that against Virginia ham, often a salt-cured, dense, intensely savory country ham rather than a mild deli ham, on soft white bread, and the sandwich becomes a study in opposition: a hard, salty, almost dry-aged meat answered by a creamy, acidic, soft spread. The pimiento cheese is the active ingredient. It is the thing that seasons, binds, and moistens, and the ham is the sharp salt-and-funk counter it exists to balance. Swap in a bland deli ham and the whole logic goes slack.
The craft is in matching intensities. A real Virginia country ham is shaved thin, because at full thickness its salt and chew overwhelm everything; sliced fine, it folds and distributes its concentrated savor across the bite. The pimiento cheese has to be sharp enough to stand up to that ham and loose enough to spread to both faces of the bread, sealing the soft crumb against nothing in particular and acting as the only source of fat and acid in the build. The bread is soft white, deliberately neutral, chosen so it carries the contrast without adding a third opinion. There is no heat in the standard build and none is wanted: the point is the cool spread against the cured meat at room temperature, a sandwich that reads as composed precisely because two strong things are held in proportion rather than blurred together.
The variations stay close to that ham-and-spread frame. Griddle it and the pimiento cheese melts into the ham for a hot, Southern take on a melt. Drop the ham entirely and pimiento cheese stands alone as its own lunch-counter classic. Run it with a milder city ham and the sandwich softens into something closer to a plain ham and cheese. Each of those is its own codified reading and deserves its own article rather than being crowded in here.