Ají de tomate de árbol

No Ecuadorian table in the Sierra, from Quito to Cuenca, is complete without a small bowl of ají, and the tamarillo version is the household favourite. Tomate de árbol, the egg-shaped, wine-red tree tomato, is blanched and peeled, blended with fresh hot chilli, salt and a little water, then finished with finely chopped onion and fresh coriander. It is spooned over locro de papa, llapingachos, empanadas de viento, hornado and fritada at the long Sunday family lunch, and onto everything at the street stalls of the Saturday markets. The flavour is tangy, fruity and slightly bitter-sweet, more sour than a tomato salsa, with a fresh bite of onion and a clean chilli heat. The common mistake is blending the tamarillos with their skins on, which makes the sauce bitter; blanch them until the skins split and slip off. It is ready when it is bright orange-red, loose and juicy, and the onion is still crisp. Abroad, tamarillos turn up in larger supermarkets; ripe plum tomatoes with the pulp of a passion fruit are the best stand-in. Chef's tip: rinse the chopped onion in salted water first, which tames its sharpness, as Ecuadorians do.