Mix the squid, prawns, carrot, shiitake mushrooms, cornflour, sesame oil, sugar and salt and pepper in a bowl with your hands until the mixture forms a paste.
Lay a dim sum wrapper in the palm of you hand and brush the edges with water. Spoon in 20g of the mixture into the middle of the dim sum wrapper, then pinch at the top to make a pirate's hat shape. Repeat until all of the mixture has been used.
Place the dim sum on an oiled plate (any oil is fine as this is to prevent the dim sum from sticking to the steamer). Place the dim sum into a steamer and cook for 4-5 minutes until the prawns are cooked.
For the dipping sauce, place all of the ingredients dipping sauce ingredients into a clean bowl and mix until combined.
To serve, place the dim sum onto a large serving plate ans garnish with baby herbs and mustard cress.