2) Deglaze the pan with the mirin. Toss in the sesame oil, soy sauce, black pepper, salt and spring onions. Let the mixture cool in a bowl.
3) Preheat a casserole or deep fryer filled with oil to 180C. Mix the tempura batter with ice cold water to pancake batter consistency.
4) Hollow out 2 tsp of avocado from the centre, then add 1/8th of the cooled prawn mixture to the cavity of each avocado; the mixture should sit securely with only 1/2 to 1/4 of mixture standing out of the avocado. Firmly press the mixture into the avocado.
5) Holding the avocado with prawn mixture, dip the entire unit into the batter and then gently lower into the oil. Cook for 2 to 3 minutes or until golden brown.
6) When cooked, remove and allow to drain on kitchen towels. Serve hot, drizzled with sweet chili sauce and sprinkled with black sesame seeds.