For the puff pastry
In a bowl, combine rice flour, chilled cubed butter, and salt. Using a pastry blender, mix hot water into the dough in small portions. Form a ball, flatten it, cover it with plastic wrap, and chill it in the refrigerator for at least 1 hour.
Take out the second chunk of the butter from the refrigerator. Flatten it with a rolling pin to the firmness of the dough. Flatten the dough and fold in the butter.
Place the dough in between plastic wrap, and roll into a 1/8 inch (5mm) thick sheet. Fold it into thirds, give it 90-degree turn, and fold it again into thirds. Cover with plastic wrap and chill in the refrigerator for 30 minutes. Repeat 2 times.
Preheat the oven at 430°F (220°C).
Roll out the dough into a 1/8 inch (5mm) thick sheet. Cut the puff pastry to make circles slightly bigger than the soup bowl.
Transfer the circles onto a lined baking sheet. Whisk the egg and brush on the puff pastry. Lightly score the pastry with a knife, making a lattice pattern.
Bake in the oven for 15 minutes.
For the stew
Peel off the shell and devein the shrimp, and cut in half. Heat the olive oil in a pot and sauté the shrimp shell.
Add 2/3 of the vegetables and garlic, and continue to sauté. Add wine and let the alcohol cook down. Add water and chicken bouillon. Simmer for 15 minutes, then strain the soup stock into another pot.
Boil the soup stock. Add shrimp, salmon, and scallops for 1 minute. Transfer them into a bowl, cover, and set aside.
Heat butter in another pot and sauté the remaining 1/3 of the vegetables. When cooked thoroughly, dust with rice flour and mix well. Pour in the soup stock and milk. When the soup thickens, season with salt and pepper.
Return the seafood into the soup pot. When heated, pour into individual bowls. Serve with puff pastry.
