The first thing to do is to soak your pasillas in ¼ cup of boiling water. Use a jug or bowl that's just big enough to hold the pasillas with a covering of the boiling water.

While they're soaking, you can set about getting a good, toasting char on the cherry tomatoes. For that, I used a heavy-bottomed 12-inch skillet.

So, set your big, dry skillet on high heat for a minute and add all the whole cherry tomatoes. You're now aiming to get a dark char onto the tomatoes as you stir them around a little for about scorching 5 minutes.

After a few minutes, the tomatoes will start to soften and flatten a little, which is what you want to happen as they char. Once they've begun to soften and flatten, drop the heat to medium-high.

Stir them a few times so you get them fairly evenly charred on that medium-high heat, and don't be too concerned if some of the tomatoes start sticking to the bottom of the skillet – a little sticking is just fine because you'll be deglazing the skillet with some of the chicken stock.

Once the tomatoes have charred and turned slightly pulpy, turn off the heat and tip the tomatoes into your food processor. Good. Time now to deglaze your skillet, so it's ready for gently frying the onion and garlic.

To deglaze, add a ½ cup chicken stock to the skillet and set it on low heat. Now use a stout spatula to scrape off all the tomato that's stuck to the bottom. This will probably take a few minutes of scraping and stirring on that low heat. Once that's done, tip everything from the skillet into your food processor, along with the charred tomatoes.

Now set your fairly clean skillet back on low-medium heat and add the lard. As soon as it's melted, stir in the onions and garlic. Keeping the heat low, you want to gently stir-fry the onions and garlic so that they soften but don't start to pick up any color. That will take about 5 minutes of very gentle frying on that low-medium heat. Once that happens, add everything from the skillet to your food processor. Time now to give the soaked pasillas some rough chopping.

Use a slotted spoon to remove the pasillas from their water and transfer them to a chopping board. Add the pasillas' water to your food processor, and then roughly chop the pasillas.

Add the chopped pasillas to the processor and blitz the whole mix to a fairly smooth paste. I like to keep a little coarseness in the paste, rather than trying to blitz it completely smooth. Good. Your broth is nearly done.

Set a large saucepan on a high heat and add the remaining chicken stock. As soon as the stock starts to boil, drop the heat to low and pour in everything from your processor. Your broth now needs to simmer slowly on that low heat for 30 minutes. When that time's up, check the broth for saltiness, and adjust according to your taste – stock cubes do vary in their saltiness, so it's wise to check the broth and perhaps add a little salt. The broth can now sit on a very low heat, so it's ready to be served once you've fried the tortilla strips.

Add the oil to your big skillet and set it on high heat. As soon as it starts shimmering, but not smoking, add 8 or so strips of tortilla and let them fry on that high heat for about 30 seconds on each side. You'll need to do this in batches so the strips can fry in a single layer with about a third-inch of space between them. Take a little watchful care with this frying because the strips turn crisp and golden surprisingly quickly in that very hot oil.

As soon as a batch is fried, lift them out of the oil with a slotted spoon, and set them to drain on kitchen towel. Then repeat the process with your next batch of strips. As soon as they're all done, you're ready to serve

For each diner, place a big, warmed soup bowl onto a dinner plate. Add 4 fried tortilla strips to the bowl and then ladle an equable serving of broth over the strips.

Now top each bowl of broth with a fair serving of the avocado chunks, spoonfuls of sour cream, and a scattering of feta cheese.

Arrange a few slices of lime around the edges of each plate, along with some strips of fried tortillas, and a few sprigs of cilantro. Done. Serve at once.