Simple Crunchy Cod Fish Sandwich

Ingredients

• 1 cup vegetable oil (for frying)
• 1 cup cold club soda or sparkling water
• 1/2 teaspoon black pepper
• 1 teaspoon salt
• 1/2 teaspoon cayenne pepper, if you want it spicy
• 1 teaspoon smoked paprika
• 1 teaspoon onion powder
• 1 teaspoon garlic powder
• 1/2 cup cornstarch
• 1 cup all-purpose flour
• 4 cod fillets, about 4-6 ounces each
• Lemon wedges to squeeze on top
• 4 slices of pickles, if that's your thing
• 4 slices fresh tomato
• 1 cup shredded lettuce or some mixed greens
• 1/4 cup tartar sauce (make it or buy it)
• 4 soft sandwich buns (brioche or Kaiser rolls work great)
• Salt and pepper as needed
• 1/4 teaspoon garlic powder
• 1 teaspoon lemon juice
• 1 teaspoon Dijon mustard
• 1 tablespoon pickle relish
• 1/2 cup mayo