First off place your block of extra firm tofu on a clean thick kitchen towel and cover it with another thick kitchen towel. Place a heavy object on it and let sit for 20 minutes. You may have to change the towels in between if they shed too much water.
Once pressed well, dab any moisture in the tofu with a napkin and chop into thick triangles or cubes.
Heat a cast iron pan or skillet with few drops of oil. Place the tofu cubes and roast from both sides for 5-6 minutes.
Now to proceed with the recipe, heat a wok or pan with 2 tablespoons sesame oil.
Add minced ginger-garlic or ginger garlic paste, slit green chili, chopped celery and cubed onions. Saute for a minute.
Add the chopped veggies and saute in high flame for 3-4 minutes.
Next add sugar, salt, chili paste and mix well.
Also add your soy sauce, vinegar and freshly cracked peppercorns. Saute in high flame for 3-4 minutes.
Now add the prepared tofu and cook for 3-4 minutes.
Throw in toasted white sesame seeds and mix well.
Remove from flame and serve with rice or use as filling for bao.