Preheat the oven to 400 degrees F.
Wrap the tofu with a towel. Put a cast iron skillet on top of it to press out the liquid for 15 minutes. Then cut it into cubes.
Simmer the soy sauce, water, maple syrup, mirin, ginger and garlic for 2 minutes.
In a bowl, whisk the cornstarch and water. Pour it into the sauce and simmer until thickened, about 3-4 minutes.