Bring a pot of water to a rolling boil. Place the tapioca starch in a mixing bowl with 1 tablespoon vegetable oil. Gradually pour in 3 1/2 tablespoons boiling water (about 50 ml), mixing well. Then add another 2 2/3 tablespoons boiling water (about 40 ml) and mix until the dough is moistened. When the dough is cool enough to handle, knead it until smooth. Cover the dough and let it rest for 30 minutes.

Clean the shrimp and cut into 1/2-inch pieces. Marinate the shrimp with 1 teaspoon seasoning powder, 1/2 teaspoon black pepper, and 1 teaspoon fish sauce. Mince the garlic and 1 shallot; thinly slice the remaining 2 shallots into rings for frying. Chop the scallions. Heat oil in a pan; when hot, fry the shallot rings until golden, then remove and set aside. Take 1 tablespoon of the hot oil and pour it over the chopped scallions to make scallion oil. Sauté the minced garlic and shallot in the pan until fragrant, then add the shrimp and cook until done. Add 1 teaspoon annatto oil for color.

Once the dough and filling are ready, take a small piece of dough (about 1/3 oz or 8 grams), roll it into a ball, then flatten it in your palm. Use your fingers to press the dough into a thin circle. Place some shrimp filling in the center, fold the dough over, and seal the edges tightly. Bring a pot of water to a boil, add the dumplings, and cook for about 5 minutes or until they float to the surface. Remove and let cool. Serve as desired; you can enjoy them with boiled eggs or Vietnamese sausage.