Traditionally, Spanish romesco sauce is made with roasted red bell peppers and almonds. Hatch chiles and pine nuts give this Catalonian sauce a Southwestern spin, and you could even sub tomatillos for the tomatoes, if you like. Hatch chiles are unique in that they come in mild, medium, hot and extra-hot varieties. I used medium Hatch chiles, which lend the sauce pleasant heat. Serve it with grilled fish or chicken, use it as a dipper with chunks of rustic bread, toss it with hot pasta, or slather it on pizza in place of tomato sauce.
Move the oven rack to the top position and preheat the broiler.
Arrange the chiles, tomatoes, and onion in a single layer on a baking sheet lined with foil. Broil 10-15 minutes or until the skins are blackened, turning halfway through cooking time.
Meanwhile, toast the bread.
Transfer the broiled chiles and tomatoes to a large bowl, cover with a plate, and let stand 15 minutes or until cool enough to handle. Peel and seed the chiles and tomatoes.
Combine the chiles, tomatoes, onion, pine nuts, and garlic in a food processor. Tear up the toasted bread, and add it to the food processor, along with the oil, vinegar and salt. Process until smooth, stopping to scrape down the sides of the bowl as needed. Transfer to a clean jar and refrigerate for up to 5 days or freeze for up to 2 months. (Makes about 2 cups.)
Notes
Don't have fresh roasted Hatch chiles? You can substitute whole canned chiles.