A whole lot of ancho chile powder, which is very mild, gives this broth its flavor and brick-red color. If you wish to substitute a different type of chile powder, proceed with extreme caution! I've also made this with about 1 teaspoon each regular chili powder and adobo sauce from canned chipotle chiles. I like the neutral-warm flavor of sunflower oil for cooking here, but any mild-tasting vegetable oil will work. Feta makes a fine substitute if you can't find queso fresco or cotija; a mild melting cheese, such as jack or locally made Toma (my favorite!), is good, too. Or leave off the cheese altogether for a vegan version. If I’m feeling fancy, I like to make a slaw out of the cabbage, red onion, cilantro, and lime seasoned with a few pinches of salt to taste, but feel free to pick and choose your toppings based on what’s available.
1/4teaspoonfine sea salt, plus another 3/4 teaspoon
5cupswater, divided use
1 1/2tablespoons(yes, tablespoons) ancho chile powder (or 1 teaspoon each regular chili powder and adobo from canned chipotle chilies, to taste)
1teaspoonsmoked paprika (a.k.a. pimenton de la vera)
3-6tablespoonsfreshly-squeezed lime juice (from 2-3 limes)
Roasted corn and zucchini:
1 1/2poundssummer squash, trimmed, in 1/2" pieces
3large ears of sweet corn
2tablespoonssunflower oil, divided
To finish the soup:
1large avocado, ripe but firm, halved, pitted, removed from the skin with a spoon, and cut into chunks
a large handful of cherry tomatoes, halved
a large handful of cilantro leaves, washed and chopped
1cupcrumbled queso fresco or cotija cheese, or grated mild melting cheese such as jack (optional)
2cupsfinely shredded cabbage (optional)
a handful finely chopped or slivered red onion (optional)
lime wedges, for serving
Make the broth:
Peel the onion and cut it in half, then cut each half into eight wedges. Place the onion, tomato quarters and garlic cloves in a 9x13" roasting pan. Drizzle with the oil, sprinkle with the salt and oregano, and toss the vegetables around to coat them evenly. Roast the vegetables until they are collapsing and caramelized around the edges, 45-60 minutes, tossing every 20 minutes to prevent the edges from burning too much (a bit of blackening is ok).
Cool the onion mixture to warm, then scrape it all into a food processor and blend to a paste. Add 2 cups of the water, blend, then strain into a large saucepan or small soup pot, pressing on the solids to extract as much good stuff as possible, leaving behind the tomato seeds and bits of skin. Discard the solids.
Add the remaining 3 cups of water to the pot along with the chile powder, smoked paprika, and remaining 3/4 teaspoon of salt. Bring the broth to a simmer, then cover, lower the heat, and simmer gently for 10-20 minutes. Let cool slightly, then stir in the lime juice, starting with the smaller amount and adding more to taste. (I like mine on the tangy side.) The broth can be made a day or two ahead and stored in the fridge; the flavor gets better and better.
Meanwhile, roast the corn and summer squash:
Place the summer squash chunks in a single layer on a rimmed baking sheet. Drizzle with 1 tablespoon of the oil, and sprinkle with a big pinch of salt. Toss to coat.
Place the corn on a small, rimmed baking sheet, drizzle with the remaining tablespoon of oil, and sprinkle with a pinch of salt, and toss to coat.
Roast the squash and corn in the oven until tender and bronzed, about 15 minutes for the corn, and 20-30 minutes for the squash, stirring and flipping the vegetables a few times for even cooking.
Make the tortilla strips:
Cut the tortillas in half, then cut them crosswise into 1/4" strips. Coat the bottom of a large, heavy skillet with a thin layer of oil and place over a medium flame until the oil shimmers. Add a single layer of tortilla strips and cook, tossing occasionally, until they are crisp and golden, about 5 minutes. Drain the strips on a paper towel or two. Repeat with the remaining strips, adding more oil if necessary.
Serve the soup:
Divide the roasted corn and squash among 6 large bowls, and add the warm broth. Top each bowl with avocado, cherry tomatoes, cilantro, queso fresco and tortilla strips, and a squeeze of lime juice.
Nutritional values are based on one of six servings.