Before you start, make sure your mixing bowl, eggs, milk, and butter are all cold for best results.

Combine yeast, sugar, flour, and salt (all the dry ingredients) in the mixing bowl with a hook attachment on speed 1. Add the milk and eggs and mix until combined, about 4 minutes. Add the butter a bit at a time. Once all the butter is added, mix on speed 3 for 15 minutes to develop gluten. (Window proof to make sure the ingredients are well combined and gluten has been developed. That means once the mixer has stopped, you should be able to pull a bit of the dough until it is translucent without breaking/tearing.)

Once the dough is formed and passes the test, set it in a bowl until the dough has doubled in size before portioning it out. (At Ugly Duckling, we leave it overnight in the fridge.)

Preheat oven to 375°. Portion dough into six equal pieces. On a parchment-lined baking sheet, place dough balls; gently press down to slightly flatten.

Whisk egg wash and brush atop dough. Bake for 18 minutes, or golden brown. Set aside to cool.

In medium mixing bowl, whisk sugar and cornstarch. Add egg yolks and mix until it is a homogenized paste, also known as a pate bomb.

In a sauce pan, heat the milk over medium heat until it simmers. Slowly add ¼ cup hot milk into the paste to loosen the consistency, mixing constantly until combined. Return mixture to sauce pan; slowly bring to a boil, stirring constantly to prevent burning, for five minutes until shiny.

Remove pastry cream from heat, stir in vanilla. Pour pastry cream into a plastic container. With plastic wrap, cover the top to prevent skin from forming. Refrigerate until ready to use.

Slice the brioche buns across their circumference.

Spoon pastry cream onto bottom half, then gently place top on.