Cod with Romesco and Hazelnuts

Name: Cod with Romesco and Hazelnuts
Ingredients: 1/3 cup blanched hazelnuts; 8 Tbsp. extra-virgin olive oil, divided, plus more for salad; 4 red bell peppers; 1 medium tomato, halved crosswise, seeds removed; 2 garlic cloves, finely grated; 2 Tbsp. sherry vinegar or red wine vinegar; 1/2 tsp. hot smoked Spanish paprika; 1/4 tsp. cayenne pepper; 4 (6-oz.) skinless cod fillets; 1 lemon; 2 cups parsley leaves with tender stems