The sultry Mulato is the dried version of a specific variety of Poblano chilli, used throughout the country by each and every cook and a key player in the famous Mole Poblano. Its flavour and gentle fire have a hint of smoky exoticism, ripe and fruity, almost chocolatey which makes it one of my favourite partners for the citrusy, sparkling taste of the indigenous tomatillo or Mexican husked tomato - it mellows the sharpness and smoothes out any overly tart edges.

This tomatillo and mulato chilli sauce is rich, deep and versatile and can be used with a steak or grilled chicken, a seafood stir-fry, roasted vegetables, etc. Its heat is temperate, making it a good accompaniment to delicate dishes, although it can be spiced up by replacing the jalapeños with bolder serranos.

My favourite way of serving this sauce is with a fried egg sitting on a lightly fried tortilla – very reminiscent in fact of that Mexican classic, Huevos Rancheros, Eggs from the Ranch, which consist of fried eggs on a tortilla topped with fresh tomato sauce. This principle applies to countless other less celebrated variations, as in the recipe below. Refried beans and/or rice are standard accompaniments to huevos of any sort, and while the whole dish is typically served for breakfast, it also makes a delicious lunch or supper.

If fresh or frozen tomatillos are not available, use tinned ones, well drained in which case you may need to sweeten more boldly.

Fried eggs in tomatillo and mulato chilli sauce – Huevos con salsa de tomatillo y mulato

Serves 4

For the sauce:-
50 g/2 oz mulato chillies
30 ml/2 tbsp olive oil
200 g/7 oz onions, peeled and coarsely chopped
450 g/1 lb fresh tomatillos, husked and rinsed
4 large garlic cloves, unpeeled
25 g/1 oz jalapeño chillies
Agave nectar, honey or brown sugar, as needed
Sea salt and freshly ground black pepper

4 tortillas
Vegetable oil for frying
4 eggs (or more if you are hungry!)
100 g/4 oz mature Cheddar-style cheese, coarsely grated
Refried beans (optional)
Cooked rice (optional)
Sea salt and freshly ground black pepper

Tear the chillies open and remove the stalks, seeds and veins. Heat a heavy frying over medium heat and toast the chillies, pressing down on them with a spatula, until they start to smell aromatic, about 3 minutes. Flip them over and do the same on the other side. Place them in a bowl, cover with boiling water, put a small saucepan lid or plate on top to keep them submerged, and set them aside to soak for 30 minutes.

While the chillies are soaking, heat the olive oil in a frying pan, add the onions and cook, stirring regularly, until they turn a light gold.

Heat the grill to high. Line a baking tray with kitchen foil, arrange the tomatillos, garlic and jalapeño chillies on it and grill about 5 cm/2 in from the heat until they start to brown on top. Flip them over and grill the underside. Cool and then skin the garlic cloves. Stem and deseed the jalapeño chillies.

Drain the mulato chillies. Place them in a food processor, add the tomatillos and any juices, garlic, jalapeños, onions and seasoning, and pour in 100 ml/3 1/2 fl oz of water. Process until fairly smooth. Scrape the sauce into the onion pan and simmer for about 20 minutes, until it has thickened. Check the seasoning and add some sweetener if it is at all sharp – the flavour needs to be well balanced and some tomatillos are very sour. Reheat.

Preheat the oven to its lowest setting and put a baking tray lined with kitchen paper to heat.

Swirl some vegetable oil around the base of a large non-stick frying pan. Place it over medium heat and when the oil starts to shimmer, lightly fry the tortillas for about one minute on each side until they are pale gold and barely crisp. With a spatula, transfer them to the baking tray in the oven.

Add a further spoonful or two of oil to the frying pan and fry as many eggs as you fancy sunny-side up. Season.

Place the tortillas on four warm plates. Slide a fried egg on to each one and top with sauce. Sprinkle liberally with cheese.

Serve immediately with refried beans and rice.

Buén provecho!

Chilli and Chocolate Stars of the Mexican Cocina by Isabel Hood is available from Amazon.co.uk

Just The Two of Us Entertaining Each Other by Isabel Hood is available from Amazon.com and Amazon.co.uk