Add all, some, or none of the jalapeño’s seeds and ribs in order to control the salsa’s heat.
- 2 vine-ripened tomatoes, halved
- 1 tablespoon vegetable oil
- 1 dried ancho chile, seeds removed
- 1 jalapeño, thinly sliced into rounds, seeds removed if desired
- 1 teaspoon distilled white vinegar
- Freshly ground black pepper
Heat broiler. Toss tomatoes with oil on a rimmed baking sheet and season with salt. Broil until skins are charred in spots, 6–8 minutes. Let cool.
Meanwhile, bring water to a boil in a small saucepan. Add ancho chile and garlic and boil, stirring occasionally, until soft, about 5 minutes. Using a slotted spoon, transfer chile and garlic to a plate; let cool. Reserve cooking liquid.
Squeeze tomatoes to remove most seeds and place in blender along with jalapeño, vinegar, ancho chile, garlic, and ¼ cup reserved cooking liquid. Blend, adding more cooking liquid as needed, until smooth, about 30 seconds; season with salt and pepper.