Matbucha (מטבוחה) is the slow-cooked tomato and pepper relish of North African Jewish kitchens, reduced until it is thick and spreadable, and as a sandwich component the angle is concentration. It is tomatoes, roasted peppers, garlic, and chili cooked down low and long until the water is gone and what remains is a dark, jammy, faintly smoky paste with a slow heat. That density is the whole point: it carries flavor without making bread wet, which is exactly what a spread has to do. Get the reduction right and a thin layer perfumes a whole sandwich; get it wrong and it is either a watery salsa that soaks the crumb or a scorched, bitter paste that overwhelms it.
The build is a long cook rather than an assembly. Ripe tomatoes are peeled and broken down, peppers are roasted, peeled, and torn, and the two go into a pan with a lot of garlic, oil, salt, and chili, then cook on a low flame for a long stretch, stirred down as the liquid evaporates, until the mixture darkens and pulls together and the oil separates back out at the edge. A good matbucha is glossy and thick enough to hold a shape on a spoon, sweet from the reduced tomato, savory from the garlic and oil, with a gentle building heat and a faint char from the peppers. A sloppy one is loose and raw-tasting because it was rushed off the heat, or burnt and acrid because it was cooked dry and scorched, or flat because it was underseasoned. As a sandwich element it is used as a spread or a layer: smeared into pita or onto bread, set under or over eggs, paired with a soft cheese, hard-boiled egg, or tuna, or used as the savory base of a stuffed laffa.
It varies first by heat and seasoning, a mild sweet version leaning on tomato, a sharp one built around chili and garlic, sometimes caraway or cumin worked in. It varies second by texture, a coarse chunky cook keeping pepper strands intact, a long smooth one breaking everything into a uniform paste. It is part of the standard mezze and salatim spread and slides naturally into sandwich work alongside its relatives, the cooked pepper salads and the fresh chopped salads, each its own form worth its own treatment rather than a line here. As a sandwich layer matbucha keeps to one idea: a deeply reduced tomato-pepper paste that adds sweet, smoky, spicy depth without adding water.