Drain the block of tofu and slice into 2-inch by 4-inch pieces, then leave on the chopping board or transfer to a tray.
In a bowl, add the lemongrass, chile, garlic, salt, sugar, and pepper. Mix all the ingredients together. With a sharp knife, cut an "x" 1/3 deep on the top of each square, then gently stuff the tofu squares with the mixture.
Heat a large frying pan over the medium-high heat. Add the oil and pan-fry each side of the tofu for 3 minutes, or until browned and crisp.
Garnish the fried tofu with coriander (cilantro) sprigs and serve with jasmine rice.