In a bowl, add the sugar, fish sauce and pour in hot water. Stir until the sugar dissolves. Add in the garlic and chillis and stir to combine. Squeeze in a wedge of lemon and taste. Add more lemon juice as required. Set it aside to cool down.
In a bowl, add in the pork mince, oyster sauce, fish sauce, white pepper, sesame oil, chopped spring onion and chopped black fungus. Mix together until it looks smooth. Cover and pop in the fridge to marinate for 30 minutes.
Take about 2 tbsp of pork and roll into a ball using the palms of your hands.
To a hot pan, add in 1 tbsp of neutral flavoured oil. Add the balls in the pan, being careful not to overcrowd the pan. Using the back of a spoon, gently press down to flatten to create the patty. Cook each side for about 4-5 minutes. You’re aiming for quite a dark colour on each side. Note that the bigger they are, the longer you will need to cook them for.
Prepare the vermicelli according to pack instructions, drain and put aside.
In a bowl, add some lettuce, Vietnamese mint, mint, perilla leaves, pickled carrot (optional), vermicelli and the pork patties. Drizzle on top the nuoc cham with spare sauce on the side for additional dipping.