Using the foil, create foil bags to put the ingredients in. Fold in half to create a dual-layer. Fold in half, fold one inch over on each side, and then fold this in half again to create a firm and secure side and a pouch to place the ingredients.
In a small bowl add the garlic, ginger, lemongrass, stock, soy sauce, and shoaxing rice wine. Stir well.
Prepare the shrimp by removing the shells and deveining them. You may remove all the shells or leave the tail on.
Add the shrimp and cauliflower to the foil pouches. Divide the stock mixture between the two foil pouches, mixing if the solids have settled to make sure the ingredients are evenly distributed.
Fold the remaining open side of the foil pouch to completely seal the foil packet.
Place over a campfire. Cook until the package heats and puffs up, this typically takes about 5 minutes. Remove from the heat.
Criss-cross cut the top of the packet from corner to corner to open. Be careful of any steam that could be very hot. Roll the edges of the foil to create a serving dish.
Garnish the shrimp and cauliflower with the sliced spring onions and cilantro leaves.