Pork Sandwich with Romesco Sauce

Ingredients

• For the romesco:
• 1 dry ancho chili
• 3 strips thick-cut bacon, chopped
• 3/4 cup drained canned or jarred piquillo peppers
• 3/4 cup drained and crushed canned plum tomatoes
• 1 medium yellow onion, peeled and thinly sliced
• 4 large garlic cloves, peeled and smashed
• 6 tablespoons olive oil
• 1/2 teaspoon smoked paprika
• Kosher salt and freshly ground black pepper
• 1 slice hearty white bread, torn into pieces
• 1/3 cup toasted slivered almonds or toasted skinned hazelnuts
• 2 tablespoons sherry vinegar
• For the pork:
• 2 tablespoons olive oil
• 1 pork tenderloin, cut crosswise into 1 inch-thick medallions
• 1 1/2 teaspoons smoked paprika
• 2 cups packed arugula
• For the assembly:
• 4 crusty rolls, such as ciabatta
• 1/4 cup mayonnaise, optional

Directions

1. Put the chili in a bowl and pour in enough boiling water to cover it. If it wants to float, set a 2nd bowl or another weight on top so it stays under the water. Let the chili soak for 30 minutes, then dry it well, pull off the stem, scrape out the seeds, and roughly chop it.
2. Move an oven rack to the upper-middle spot and heat the oven to 425 degrees F. Fit foil onto a large, rimmed baking sheet. On that sheet, combine the chili, bacon, peppers, tomatoes, onion, garlic, 1/4 cup olive oil, and smoked paprika; add salt and pepper.
3. Roast for 30 to 40 minutes, until the onions have softened and picked up a little char, stirring the mixture at the halfway point. Set the baking sheet on a cooling rack and let everything cool for 15 minutes.
4. Pulse the bread in a food processor until coarse crumbs form. Add the roasted pepper mixture, nuts, vinegar, and the remaining 2 tablespoons olive oil. Taste and season with salt and pepper. If you are working ahead, the romesco can be made 1 week in advance and refrigerated in an airtight container.
5. In a large skillet, warm 1 tablespoon oil over medium-high heat until it just starts to smoke. Blot the pork with paper towels, sprinkle with salt and pepper, and coat it all over with smoked paprika.
6. Cook the pork for 3 to 4 minutes per side, so each side browns. Move it to a large bowl. With 2 forks, pull the pork into bite-sized pieces.
7. Add the remaining 1 tablespoon oil to the empty skillet and set it back over medium-high heat. Return the pork to the pan and cook, stirring now and then, until it turns crisp and golden, about 5 minutes. Fold in the arugula.
8. Cut the rolls in half, then coat the inside of each top piece with 1 tablespoon mayonnaise. Spoon a heaping 1/4 cup romesco onto the bottom half of each roll.
9. Divide the pork evenly over the romesco-covered bread, close the sandwiches with the mayonnaise-side tops, and serve.