Tempura Cod Bites with Samurai Sauce

Ingredients

• 1/2 cup 1/2 cup mirin
• 1/4 cup 1/4 cup low-sodium soy sauce
• 1/4 cup 1/4 cup rice vinegar
• 2 teaspoons 2 teaspoons minced and seeded serrano peppers
• 1 Tablespoon 1 Tablespoon minced green onion or chives
• 1 pound 1 pound Alaska Cod fillets, fresh, thawed or frozen
• 1/3 cup 1/3 cup mayonnaise
• 1/4 teaspoon 1/4 teaspoon cayenne pepper, if desired
• 2 teaspoons 2 teaspoons lime juice
• Salt
• pepper
• 1/4 1/4 to 1/3 cup panko bread crumbs
• 1/4 cup 1/4 cup furikake (shredded nori and seasonings), if desired
• 3/4 cup 3/4 cup tempura (dry batter)
• Ice cold water, as needed
• Peanut or canola oil, for frying