To prepare the crab, pull the top shell away from the body, and remove gills. If using blue swimmer crabs, cut into quarters, if using mud crab, twist off the claws and divide the body into quarters.
Pulse the ingredients for the base paste in a food processor or blender until you have a paste consistency.
Heat a wok over medium heat and add the oil. Fry base paste for about five minutes, until fragrant. The oil will start to separate from the solids.
Add the crab and shell into the wok and toss to coat the crab. Add Mutti Polpa, Tomato Paste, vinegar, water, sugar and soy and toss to coat. Cover the wok and simmer for 5-10 minutes, depending on the size of your crab pieces.
Add the spring onions and toss through. Remove the crab and spring onion pieces and set aside. Add the cornflour mixture and stir until thickened. Slowly drizzle in the egg mixture while stirring.
Place half the sauce on the bottom of a large serving dish, top with crab and finally pour remaining sauce on top. Scatter with coriander and sliced chilli to serve.