In a small bowl, combine the lukewarm milk, dried yeast and 1 tsp of sugar and stir thoroughly. Set aside for the yeast to activate (bloom).
1/3 cup sugar, 1 1/2 tsp active dry yeast
In a large mixing bowl, combine the sifted flour, remaining sugar, and salt. Add the yeast mixture, the whisked egg, and vanilla extract. Mix everything with a handheld electric mixer or stand mixer with a dough hook on medium speed for about 5 minutes. The dough needs to be smooth and pass the windowpane test.
1 pinch salt, 4 cups all-purpose flour, 1 tsp vanilla extract, 1 egg, 1/3 cup sugar
Cut the unsalted butter into 1-inch cubes and knead it into the dough one after another on low speed.
Scrape down the sides of the bowl and form a large ball of dough. Cover the bowl with a damp kitchen towel or plastic wrap. Let it rest in a warm spot for 45 minutes for the first rise.
Line a baking tray with parchment paper.
1/2 cup chocolate chips
Transfer the soft dough to a lightly floured surface, roll it out into a 9x9 inch square using a rolling pin, and add the chocolate chips evenly. Roll the dough up from one end and cut the roll into 8 evenly sized portions.
Using your hands, roll each portion into an 8-inch log. To make the knotted buns, start by creating a U shape with the log. Twist the two top ends around each other twice. Fold the twisted top down into the hole and tuck it in. Place it on the lined baking sheet and repeat the process for the other buns.
Cover with a tea towel and let the rolled buns rest for about 15-20 minutes for a second time for the final proof.
Preheat the oven to 180C/356F.
Brush the chocolate chip brioche buns with the egg wash and bake them in the preheated oven for 20 minutes until golden brown. Let them cool down a little and serve them warm!
1 tbsp milk, 1 egg yolk