Put 1 tbsp dry active yeast in 2 tbsp warm water. Let proof.
In a bowl of a stand mixer, put butter, salt and sugar.
Mix with the flat beater attachment or hook attachment.
Add the 2 eggs and vanilla extract then mix more. The mixture may not look homogeneous but it will be after adding flour.
Add 1 cup flour first and the yeast mixture.
Mix everything.
Add the rest of the flour 1/2 cup at the time and mix everything well. Make sure you scrape the sides of the bowl to gather the dough.
Sprinkle some flour on the very soft and sticky dough then gather the it into a ball.
Cover the dough in the same bowl (or another bowl) with plastic wrap and kitchen towel.
Let rise until doubled in volume.
Sprinkle flour on a working board.
Use a rolling pin to roll out the dough into a thin rectangle shape.
Spread pastry cream on half of the rectangle of dough(lenghthwise).
Put chocolate chips on the pastry cream.
Use the back of the spoon to gently press on the chocolate chips and make sure they stick to the cream.
Fold the other half of the rectangle of dough on the chocolate pastry cream.
Seal all the edges.
Use a knife to trim 3 sides of the rectangle to make it nicer if you want or just make it nice by hands.
With a knife, cut the long rectangle into smaller rectangles (about 3 fingers wide).
Place the cut out pieces on a baking sheet lined with parchment paper. Make sure to leave space between them.
Cover with kitchen towel and let rise for about 30 minutes.
Brush the brioche with egg wash.
Bake in a 350°F preheated oven for about 15 to 20 minutes (depending on your oven) or until golden. You may place under the broiler in the last 5 minutes of baking.
Brush the Brioche top with syrup.
Enjoy.