Place the sesame oil into a small saucepan over low heat. Add in the ginger and garlic, toss with the oil to coat, and allow to soften for about 10 minutes, stirring occasionally. Do not allow the garlic or ginger to brown.
Add in the chopped scallions, stir, then increase the heat to medium. Saute for about 2 minutes, or until the scallions are bright green, then increase the heat to medium high.
Once the pan starts to sizzle, add in any hot pepper powder (if using), then deglaze it with the mirin or 2 TB of broth. Next, add in the 1 cup of broth, soy sauce and rice vinegar, then stir in the sugar. Allow the mixture to come to a small boil, then whisk in the cornstarch slurry and stir until thickened. Set aside to slightly cool.
To make the tofu
Heat the canola oil in a skillet over medium heat. Cut your block of tofu into 4 slabs, then cut each slab diagonally to make 8 triangles. Carefully place the tofu into the hot pan, then cover and increase the heat to medium high. It will pop and sputter for about 10 minutes. Carefully lift the lid up to prevent and water from hitting the hot skillet, flip the tofu and allow to saute, uncovered, on the other side for about 5 minutes or until nicely browned. If the tofu starts to stick, reduce the heat and add a little more oil, shimmying the pan back and forth over the heating element to loosen.
Remove the skillet from the heat, then toss in some of the sauce directly in the skillet to coat. Serve with steamed broccoli and rice, drizzling with any extra sauce. Top with raw sliced scallions, peanuts and thai chilis, if desired.
Recipe by Olives for Dinner at http://olivesfordinner.com/2013/07/tofu-with-general-tsos-sauce.html