Prepare Romesco sauce:
In a food processor, grind the almonds. Add roasted peppers, garlic, bread, parsley, and hot pepper flakes. Blend until it becomes a paste. Add the vinegar and pulse to blend. With the motor running, gradually pour the olive oil through the feed tube in a steady stream until the mixture thickens like mayonnaise. Season to taste with salt and black pepper.
Store in a covered container in the refrigerator for up to 3 days.