Cornstarch-coated tofu cooks separately before joining a coconut, tomato and chili sauce. Press and dry firm tofu first so its coating has a chance to brown. Add it back near serving; once coated in sauce, the crust will gradually soften. Dry the pressed tofu before coating it so the measured cornstarch sticks to its surface instead of forming wet clumps in the bowl. Give the cubes room in the skillet and let a browned face release before turning; repeated stirring can break the corners. Stir the coconut milk thoroughly before adding it, incorporating the thick cream and thinner liquid from the same can. Keep the sauce at a gentle simmer. Return the tofu near serving time: its coating will soften once it sits in the sauce, so this is a sauced tofu dish rather than a promise of lasting crispness. Taste before adding salt because soy sauce and chili-garlic sauce already contribute seasoning.