Roughly chop the lemongrass into chunks and blitz it using your blender or food processor. If you don't have either, you can finely mince the lemongrass into very small pieces. Set aside about ¼ of what's there in a bowl for now. *Lemongrass has a tough texture, so unless you like that I suggest getting it as small as possible.
Pat dry (or press) and slice tofu into 1/2 inch thick slices. * To press the tofu, weigh the whole block of tofu between a towel and two cutting boards with a heavy object on top for 10 minutes before slicing it.
In a blender, mix up ¾ of the total minced/blitzed lemongrass, the soy sauce, ½ of the total chili flakes, and salt. This is the tofu marinate. Cover the tofu with this marinade and let sit for 15-mins.
Place a pan over medium heat. Once the pan is hot, add cooking oil. With your finger, wipe away aromatic chunks and set them aside. Now, add the tofu slices to your pan in a single layer. It's all good if some aromatics stick to the tofu slices. Fry until golden and crispy, flip once or twice.
Transfer the fried tofu to a plate with paper towel or a kitchen towel (to absorb excess oil).
Clean off the pan of any burnt bits and put the pan back on the stovetop at med-low heat – with no oil.
Add the aromatics from the marinade and the excess lemongrass to the pan, then stir and toast until lightly golden. Then, add the garlic, and the rest of the lemongrass and chili flakes, and continue toasting until they are a deep golden colour and crunchy.
Place tofu slices on a serving plate and sprinkle all the golden-toasty aromatics on top. Serve immediately.
Make sure you peel off the outer layer of the lemongrass stalks and *discard the green fibrous part. For the toasted aromatics to turn out crunchy, use only white (and very light green) tender parts and mince as finely as you can. Be patient when toasting.
*You can compost this, or add it to your next soup stock.