Use a grater such as a Microplane to grate the white part of the lemongrass, about 2 tablespoons. Use a mortar and pestle or the back of a knife to pound and smash the grated lemongrass to release its aroma and flavor.
Rinse the chicken wings with cold water and pat dry. Transfer the wings to a large bowl; add the lemongrass, honey, garlic and fish sauce, if using. Combine well, making sure the wings are nicely coated. Let marinate in the fridge for at least an hour.
Preheat the oven to 400 degrees. Grease a baking sheet with the oil or fat.
Spread the marinated chicken evenly on the prepared sheet. Roast for 15 minutes, rotate the sheet and toss the chicken; then roast for another 15 minutes, until the chicken is nicely colored and cooked all the way through. Season with salt, if needed.
Place chicken on a large platter and serve while still hot.