While the tofu is draining, in a small bowl dissolve the cornstarch in 1/4 cup of the water and stir in the remaining 3/4 cup water, the soy sauce to taste, the vinegar, the Scotch, the sugar, and the salt. In a heavy saucepan heat 1 1/2 tablespoons of the vegetable oil over moderately high heat until it is hot but not smoking and in it stir-fry the garlic until it is pale golden, being careful not to let it burn.