1 ripe tomato, finely chopped
2 tablespoons finely minced white onion
3 chiles serranos, finely chopped
1/2 teaspoon sea salt
3 large avocados, preferably Haas
2 tablespoons finely minced fresh cilantro

Put the tomato, onion, chiles and salt in a small bowl and smash with a pestle or fork to a coarse paste. Cut avocados in half, remove pits, and scoop the flesh into the tomato mixture. Use a spoon to scrape out any pulp remaining on the skin. Add minced cilantro and mix and mash, leaving some lumps. Taste and adjust with more salt.

Serve at once, if possible. To keep at room temperature for up to 1 hour, cover with plastic wrap, pressing it directly on the surface. To keep for up to no longer than 3 hours, do not add the cilantro till just before serving, and cover and store in the refrigerator.