Creating the Crunchy Chicken Romesco Sandwich is straightforward if you follow these simple steps:

1. Marinate Chicken: Place the chicken breasts in a bowl and cover them with buttermilk. Let them marinate in the refrigerator for at least 30 minutes.
2. Prepare Coating: In a shallow dish, mix the flour, paprika, garlic powder, onion powder, salt, and black pepper.
3. Coat Chicken: Remove the chicken from the buttermilk, allowing excess to drip off. Dredge each breast in the flour mixture, ensuring an even coating.
4. Add Breadcrumbs: Press the coated chicken into the breadcrumbs to create a crunchy layer.
5. Heat Oil: In a large skillet, heat oil over medium-high heat. Ensure there’s enough oil to submerge the chicken halfway.
6. Fry Chicken: Once the oil is hot, carefully add the chicken breasts. Fry for about 6-7 minutes on each side or until golden brown and cooked through (internal temperature should reach 165°F/74°C).
7. Drain: Remove the chicken from the skillet and place on a paper towel-lined plate to absorb excess oil.
8. Assemble Sandwich: Slice the sandwich rolls in half. Spread a generous amount of romesco sauce on the bottom half. Place a piece of crunchy chicken on top.
9. Garnish: Add fresh parsley if desired for a pop of color and flavor. Top with the other half of the roll.
10. Serve: Enjoy the sandwich warm and fresh!