Soak dried mushrooms overnight in ⅓ cup of water. Save the water for cooking the filling later.
In a large pan with some oil over medium heat, cook the shallots first. Stir in the minced garlic and white parts of the scallions until fragrant.
Add in the jicama, carrots, mushrooms and spices, cooking for one minute. Stir in the sauces until everything is well combined. Pour in the mushroom water, turn the heat to low and cover the pot with a lid. Let simmer for 5 minutes.
Remove the lid and let the excess water has evaporated. The vegetables should have softened by now. Turn off the heat and stir in the remaining scallions. Set aside to cool.
Sift the dry dough ingredients together. Pour in boiling hot water and mix with a spatula until a sticky dough forms. Once the dough is cool enough to touch, knead it with your hand to incorporate the flour better. The dough should look slightly translucent. Drizzle in the cooking oil and continue kneading until a white, pliable dough forms. It's normal to have small lumps of starch still in the dough.
Roll the dough into a log and divide it into two parts. Roll out half of the dough into a log and divide into 6 pieces. Repeat with the other half and you should get 12 pieces of dough, 25 g each. Roll each piece between your palms to form a ball.
Cover the dough balls with plastic wrap or a damp cloth to prevent them from drying out as you work. With a small rolling pin, flatten a dough ball out into a small round, turning the dough in between each roll. Pat the dough with oil if it starts to stick. You should just be able to see the colour of your palm through the dough. Don't roll it out too thin, or it will tear later on.
Continue to roll only the edges of the dough. Use the same turning and rolling method as above. The edges should be thinner than the center of the dough.
Place one heaping tablespoon of filling in the center. Pinching the opposite sides of the dough together with your left hand, pleat the dough 3-4 times with your right hand from the center to the right. Repeat with the other side.
Steam the dumplings on a parchment paper lined/oiled pan with boiling water for 5-8 minutes. Brush the steamed dumplings with sesame oil and top with sesame seeds. Serve fresh with a dipping sauce. Enjoy!