Serrano is a staple of Mexican cooking — a smaller, hotter, and more intensely flavoured version of the jalapeño without the thick walls. Widely used in fresh salsas (salsa verde traditionally uses fresh serrano rather than jalapeño), guacamole, and any preparation where a bright, direct chilli heat is needed. The flavour is greener, fresher, and more assertive than jalapeño.
Flavour
Bright, direct, fresh green heat (10,000–23,000 Scoville) with a grassy intensity that's cleaner and more assertive than jalapeño. The thinner walls mean the flavour is more concentrated — all heat and bright green chilli character. Ripening to red adds sweetness and mellows the raw grassiness into something richer and more complex.
In the kitchen
Essential in fresh salsa verde and guacamole. Excellent finely diced and added raw to any fresh preparation where bright, direct chilli heat is needed. Roast over direct fire until blistered for a roasted salsa. Less suited to stuffing (thin walls) but excellent grilled whole as a fiery side condiment to grilled meat.
Growing
Sow under glass in January–February. Grow in the same way as jalapeños but plants tend to be more compact and slightly earlier. Highly productive under glass in UK conditions. The small fruit size means a single plant produces hundreds of chillies over a season. Harvest green for fresh use; allow to ripen to red for drying.