Brush the bottom of a glass pyrex dish with olive oil and place the tofu in the dish. Place in the freezer overnight.
To defrost the tofu, place it in the oven at the lowest setting for 15-20 minutes. Remove it from the oven and press it thoroughly for an hour, ensuring that it is almost bone-dry before placing it into the marinade, which you can make by whisking together the broth, soy sauce, garlic and ginger.
You can skip freezing/defrosting the tofu for this recipe, but thorough pressing is a must. Freezing/defrosting transforms the texture of the tofu by making it more “meaty” and dense. Marinate for at least 4 hours.
When you are ready to make the tofu, dissolve the sugar in the boiling water, then add the vinegar and dash of salt. Set aside.
Saute the tofu for about 5 minutes on each side over medium-high heat, or until a good sear is achieved.
To plate the tofu, pour some of the vinegar mixture into a shallow bowl.
Arrange the tofu on top of that, sprinkling with the chopped scallions. Finish by adding several droplets of the chili oil. Serve immediately.