• Make the dough. In a small saucepan, warm milk gently to about 105–110°F. Remove from heat and whisk in yeast until dissolved. (If your milk gets too hot, let it cool down before adding yeast.) Set aside.

Pulse flour, salt and cardamom in food processor to combine. Pulse in butter until it resembles coarse meal, about 20 pulses. Empty mixture into bowl of stand mixer. Add sugar, egg and milk/yeast mixture. Using the hook attachment on medium speed, mix dough together until well combined, about 2 minutes. Cover bowl with a towel, place in a warm spot and allow to rise for 30 minutes.

Make the custard. In a small saucepan, whisk together eggs, sugar, cornstarch and vanilla. Add the milk. Heat the mixture over low heat until it comes to a complete boil, whisking constantly. Remove from heat and allow to cool to room temperature.

Preheat oven to 375°F. On a lightly floured surface, gently roll out the dough to a rectangle approximately 17″ x 13″. Cut a 3 x 4 grid on the dough. Divide the custard evenly among each square, about 1 heaping teaspoon per square. Carefully, gather two opposite corners of each square up over the custard and pinch to fasten. Repeat with remaining two corners so that all four corners meet. Pinch the side seams together so that no custard will escape during baking. Turn the dough over in your palm and ensure that the bun is smooth-looking and round and place on a parchment-lined baking sheet. Repeat with remaining squares. Allow buns to rise for 30 minutes. Bake until pale brown, about 15 minutes. Cool buns on cooling rack to room temperature.

Make the icing. Sift together the confectioners sugar and cocoa powder in a medium bowl. Slowly stir in the water and vanilla. Dip the tops of each cooled bun into the icing and allow to set briefly before serving. These buns taste best when they are eaten the same day.