This recipe is really all about the tomatoes. For the best results, make these tacos in summer, when tomatoes are at their sweetest and seasonal best. Thicker-fleshed varieties, like Romas, work better for this filling, as they give off less juice and cook down to a firmer consistency. After roasting, the tomato slices turn soft and crinkly.

Thin shavings of buttery, piquant Spanish Manchego cheese make a wonderful addition, as do leaves of peppery arugula or sprigs of cilantro. Pumpkin seeds are available toasted, which deepens their flavor, or you can easily toast them yourself in a hot, dry skillet.

These tacos can easily be served in place of a salad course for a dinner party. The pesto will hold for one week in the refrigerator and shines with pastas, seafood, or meat dishes. For a quick version, substitute about four ounces purchased roasted tomatoes, stocked at specialty markets. Look for them in bulk where olives are sold, packed with herbs and a bit of oil.

Steps

1. Preheat the oven to 200 degrees. Line a baking sheet with parchment paper.
2. Halve the tomatoes across their midsections and gently squeeze the halves to release seeds and excess juice (the tomatoes will cook faster). Slice the tomatoes thinly. In a bowl, toss the slices with ½ teaspoon of the salt and the sugar. Spread the slices in a single layer (so the tomatoes are evenly exposed to the heat) on the prepared baking sheet. Roast for at least 2 hours, or until the tomatoes are about three-fourths dehydrated and the flesh is the consistency of a roasted bell pepper (they’ll resemble soft sundried tomatoes). The slices will shrink by about half during roasting; no need to turn them. Remove from the oven and set aside to cool down to room temperature.
3. Cut the prepared poblano chiles into ¼-inch-thick strips and set aside.
4. In the work bowl of a food processor fitted with the metal blade, combine the pumpkin seeds, chile powder, olive oil, lime juice, cilantro, and remaining 1½ teaspoons salt. Process to the consistency of ground almond butter (a little rougher than peanut butter) or as you prefer.
5. To serve, lay the tortillas side by side, open face and overlapping on a platter. Divide the pesto equally between the tortillas and top with roasted tomato slices, chile strips, salsa, and basil. Grab, fold, and eat right away. Or build your own taco: lay a tortilla, open face, in one hand. Spoon on some pesto, top with tomato slices, chile strips, salsa, and basil, and eat right away.