At least 1 hour before (overnight is better), marinate the protein: crush 1 tablespoon of sugar, the ginger, garlic, lemongrass, and Thai chili (if using) in a mortar and pestle. Combine with your protein of choice with the fish sauce, oyster sauce, and oil. Mix well, then cover and store in the fridge.
Add a bit of oil to a skillet and fry your protein until well charred on both sides, in batches, depending on your skillet size. Remove from the pan.
One at a time, dip the rice paper into a bowl of warm tap water. Lay it out on a flat surface.
To the bottom third of the round, add a leaf or two of lettuce, then the protein, a small amount of vermicelli, vegetables, and herbs.
Fold up the bottom of the rice paper wrapper up and over the filling.
Fold in the two sides over the filling.
Roll up, from the bottom of the roll towards the top, tucking and rolling. Repeat as needed and enjoy dipped in your sauce of choice.
Estimated nutrition assumes chicken breast as the protein.