A lasagna with a short fuse

This is what happens when the golden lasagna spends a summer in the Southwest and comes back with opinions. The carrot puree is still the soul of it, only now it is smoked and spiced, with sausage and charred poblano running through the layers and a cold lime cream to call the fire brigade. Not light, exactly. Worth it, entirely.

1. First char the poblanos, straight over a gas flame or under the broiler, turning until the skins blister black all over. Seal them in a covered bowl to steam for 10 minutes, then rub off the skins, pull out the seeds and slice the flesh into strips. Those strips have a name, rajas, and they are worth the small faff.
2. Warm the olive oil in a skillet with the carrots, onion, garlic, cumin and the teaspoon of salt. Stir to coat, add the vinegar and stock, and cook on medium, partially covered, about 20 minutes, until the carrots are completely soft and the liquid has nearly gone. Blitz smooth with the minced chipotles and their adobo. The puree should come out a deep smoky orange-red.
3. In the same skillet, brown the sausage over medium-high, breaking it into craggy bits, until deeply colored and crisp at the edges. If you are using the corn, tip it in for the last minute or two to warm through and catch a little color.
4. Beat the ricotta smooth with a big spoonful of the puree, the egg, the lime zest and the half-teaspoon of salt. The egg is not there for richness, it is there for structure: with no béchamel to bind the layers, it is what sets the ricotta as it bakes so a cut slice holds its lines instead of sliding off the spatula.
5. Make the lime cream. Stir the yogurt with the lime juice, a little more zest and a pinch of salt, loosening it with a splash of water until it ribbons off a spoon. Chill it while the lasagna bakes. That cold, sharp drizzle against the smoky heat is the whole point of the dish, so do not skip it.
6. Heat the oven to 350°F convection. First ready the pasta. Boil regular dried sheets for about half the time on the box, since they finish in the oven, then lay them flat, or use oven-ready no-boil sheets dry and loosen the puree with an extra splash of stock so they soften as they bake. Assemble in a baking dish: a scrape of the smoky puree on the base, then pasta, then whipped ricotta, a little more puree, a scatter of sausage, a few poblano strips and a handful of mozzarella. Pasta again, and repeat. On the final layer before the top sheet, be generous with the mozzarella. Lay the last pasta, spread a veil of puree and finish with the rest of the mozzarella.
7. Bake for about 1 hour, until bubbling and blistered on top. If you used no-boil sheets, cover with foil for the first 40 minutes, then uncover to finish. Let it settle for 5 minutes.
8. Finish with crumbled cotija, torn cilantro and, if you want the crunch, a handful of crushed tortilla scattered over the top. Cut it, and ribbon the cold lime cream over each fiery slice.

To send it back to Italy, swap the chipotles for a good spoonful of Calabrian chili in the puree, leave the corn and poblano out, keep the Italian sausage and reach for parmesan over cotija, then finish with torn basil and skip the lime cream. Same golden bones, a fruitier heat and a calmer table.