4 raw king prawns or 8 raw large shrimp, peeled and deveined
4 small scallops or fillets of flounder (or any white fish) cut into 1- to 2-inch pieces
4-8 shiitake or button mushrooms, stems trimmed and cut in half, if large
8 asparagus tips, about 2 inches long
1 cup ice-cold water
1 1/2 cups cake flour (or all-purpose), sifted
1 to 4 cups vegetable oil for frying
After preparing the ingredients, dry them with paper towels to ensure that the batter sticks evenly. In a large sauce pot or Dutch oven over medium heat, heat oil (enough to cover the tempura pieces by 1 inch) to 375 degrees. Adjust heat if necessary to maintain temperature. In a mixing bowl, lightly beat the egg. Gently mix in water (without ice). Add sifted flour all at once and stroke a few times with chopsticks or a fork until loosely combined. Batter should be lumpy, not smooth and velvety. Test the oil heat by dropping in a small bit of batter; it should descend slightly beneath the oil then rise to the surface bubbling gently around the edges. Use fingers to dip ingredients into batter. Allow excess to drip off, then gently place in oil. Cook several pieces at a time, but do not overcrowd the pan. Cook for about 3 minutes, turning periodically to cook evenly. Remove the tempura from oil, briefly drain on paper towels, and serve immediately with dipping sauce.