In the bowl of a stand mixer, combine the flour, granulated sugar, salt, and crumbled yeast. Mix until all ingredients are well-integrated.

Pour in the beaten eggs and knead at medium speed for about 3 minutes until well combined. The dough will start to form and take shape.

Gradually add the softened butter while kneading the dough for about 20 minutes until it achieves a smooth and sticky consistency, perfect for brioche.

Cover the dough with a clean kitchen towel and allow it to rise in a warm place for about 120 minutes or until it has doubled in size.

In a saucepan, heat the milk and butter together with the split vanilla bean. As it warms, the delightful aroma will start filling your kitchen.

In a separate bowl, whisk together the egg yolks, granulated sugar, cornstarch, and flour until smooth. Slowly incorporate the hot milk mixture, carefully adding it to prevent curdling.

Return the custard mixture to the pan over medium heat. Cook while stirring until it thickens, then transfer it to a bowl and let it chill in the refrigerator.

Once the dough has risen, roll it out on a floured surface. Spread a generous layer of chilled custard on half the dough and sprinkle mini chocolate chips over the custard.

Fold the dough over and cut it into rectangles. Allow them to rise again for 120 minutes, covered.

Preheat your oven to 350°F (177°C). Gently brush the risen brioches with the beaten egg yolk mixture.

Bake for 10-12 minutes until they are golden brown.

Create the simple syrup by boiling sugar and water together until dissolved. Brush the warm brioches with this mixture.

Allow the brioches to cool on a wire rack before serving.