In a large bowl, combine the bread flour, cake flour, and fine sea salt. In another bowl, mix the warm milk, heavy cream, sugar, and yeast. Allow it to sit until bubbly – about 5 minutes.

Once it's frothy, add the egg to the milk mixture and stir well. Gradually mix the wet ingredients into the dry flour mixture. Knead the dough on a floured surface for about 10 minutes, until smooth. Place it in a bowl, cover with a damp cloth, and let it rise in a warm area for 1.5 to 2 hours, or until it doubles in size.

While the dough rises, let’s make the filling. In a pan, heat the vegetable oil over medium heat. Add chopped shallots and sauté until fragrant. Stir in the diced char siu pork.

Next, add chicken broth, dark soy sauce, oyster sauce, light soy sauce, sesame oil, sugar, and ginger. Allow the mixture to simmer for about 10 minutes. Mix the flour into the filling to thicken it. Once done, let the filling cool.

After the dough has risen, punch it down to release the air. Divide the dough into equal pieces (about 12 or 16, depending on your preference). Flatten each piece and place a generous spoonful of filling in the center. Gather the edges and pinch to seal tightly.

Line a steamer basket with parchment paper. Arrange the buns, leaving space between each for expansion. Let them rise for another 30 minutes before steaming.

Bring water to a boil in your steamer. Place the buns in the basket and steam for about 15 minutes, or until they puff up. Ensure the water doesn’t touch the buns.

Mix the sugar water and brush it lightly over the buns once cooked to give a shiny finish. If using sesame seeds, sprinkle them on top at this time