This versatile, spicy yellow sauce is the perfect accompaniment to roasted tofu, seitan, vegetables, french fries, and fried yuca. * The star ingredient is the aji amarillo chile pepper, a staple in Peruvian cooking. Look for jarred aji amarillo (yellow) paste in a Latin food market. If you can't find the paste, you can use frozen aji amarillo peppers. Thaw and dice one pepper, and saute it in olive oil until it's soft. Add the cooked pepper to the rest of the sauce ingredients and process. Recipe from Vegan International.