Pat dry the shrimps with paper towels. Place the chopped shrimps in a medium mixing bowl. Add in 1 teaspoon of cornstarch and 1/4 teaspoon of salt.
Place the ground pork in a large mixing bowl. Pour in 1 tablespoon of cornstarch, white pepper, sugar, Shaoxing wine, soy sauce, fish sauce, sesame oil, and chicken stock.
Squeeze and mix the seasoned ground pork with your hands, then throw it against the mixing bowl until it resembles a paste-like consistency. Wash your hands and do the same with the seasoned shrimps. Put the pastes into the fridge and prepare the remaining ingredients.
Finely chop green onions and re-hydrated shiitake mushrooms. Grate the ginger slices.
Remove the pork and shrimp pastes from the fridge. Pour all the ingredients into the ground pork paste mixing bowl. Squeeze and mix the ingredients with your hands until blended. Remember to throw the paste against the mixing bowl!!
Place a wonton wrapper on one hand. Scoop roughly 3/4 - 1 tablespoon of mixed paste on the wonton wrapper with a butter knife or the dull end of a spoon. Then, wrap it into a cylinder shape with an open top.
Place a parchment liner into the bamboo steamer, then place the Shumai on the liner. Close the bamboo steamer lid.
Place a steamer rack and pour one cup of water into the Instant Pot. Place the bamboo steamer filled with Shumai into the pressure cooker. Close lid and cook on Manual at High Pressure for 3 minutes. Wait for another 5 minutes and do a Quick Release.
Remove the bamboo steamer from the pot and enjoy them immediately!