Roughly chop 4–5 medium plum tomatoes and a quarter of a medium white onion. Trim the stem from a jalapeño (remove the seeds for a milder salsa, if you like) and peel one garlic clove.
Place the chopped tomatoes, onion, jalapeño, garlic, 120 ml packed fresh coriander leaves (including tender stems), 15 ml freshly squeezed lime juice and 2.5 ml salt into a food processor or blender.
Pulse the mixture in short bursts (about 5–10 pulses) until it reaches your preferred consistency – chunky or slightly smoother.
Tip the salsa into a bowl, taste and adjust with extra salt or lime juice to suit.
Serve straight away with tortilla chips or use it as a topping. Store any leftovers in an airtight container in the fridge for up to 3–4 days.