Sauce: Combine the ginger, shallots and garlic together in a saucepan. Add the sugar, white wine and rice vinegars, tomato paste, water, and Sriracha sauce. Stir to blend and bring the mixture to a simmer. Cook gently, stirring frequently, for about 8 minutes. Whisk cornstarch mixture into the sauce. Add a few chopped leaves of the basil, cook for a minute or two more, remove from heat and let cool. Refrigerate until serving time.
Calamari: Rinse the squid well and cut the steaks into strips about 1 1/2 inches wide, or cut the tubes into rings. Pat dry thoroughly with paper towels. Pour the buttermilk into a wide bowl, and put the seasoned flour in a second wide bowl. Pour oil into a deep pan (or covered fryer) to a depth of 3 to 4 inches.
Heat the oil to 350° F.
Dip a handful or so of the squid into the buttermilk, let drain, then toss into the flour. Coat well, then place squid in a strainer, hold it over the sink and shake off the excess flour. Place the squid into the hot oil and carefully separate the pieces, taking care to avoid any spattering oil. Cook briefly, about 2 minutes for the strips of steak, and just 1 minute for the rings and tentacles. The coating should be golden brown. Remove and drain on paper towels. Serve immediately along with the sauce, garnished with chopped basil.Makes 6 appetizers Source: