Mix together the sugar, cornstarch, salt, and egg yolks in a medium bowl.

Add the milk to a medium saucepan over medium heat. Once the milk is steaming hot, whisk in the vanilla and vanilla bean paste.

Return the saucepan to the heat and turn it down to low. While whisking constantly, continue cooking until the mixture is thickened, about 1 minute.

Remove from the heat and whisk in the butter.

Immediately (while the pastry cream is still hot), strain it through a fine mesh sieve into a bowl, using a spatula to press it through. Place a piece of plastic wrap directly on top of the pastry cream.

Let it cool to room temperature (about 30 minutes), and then transfer it to the fridge to fully chill (about 3 hours). It will thicken during this time.

Add the flour, sugar, yeast, and salt to the bowl of an electric stand mixer. Whisk to combine.

Add the egg, egg yolk, milk, and vanilla bean paste to the flour mixture. Use the dough hook attachment on the stand mixer to mix on low speed until the ingredients come together and start to look like dough.

With the mixer still on low speed, add the room temperature butter 1 tablespoon at a time until it’s fully mixed in. Wait to add the next tablespoon of butter until the previous one is fully incorporated.

Once all the butter is mixed in, turn the mixer speed to medium and knead for 10 minutes.

Oil a large bowl. Use your hands to shape the dough into a ball and place it in the oiled bowl, rolling it around to coat. Cover the bowl with plastic wrap or a clean kitchen towel.

Let the dough rise at room temperature until doubled in size, about 90 minutes to 2 hours.

Gently deflate the puffed dough. Cover the bowl again, and let it rise for 30 minutes.

Line 2 large baking trays with parchment paper or silpat baking mats.

Roll the dough out between 2 pieces of parchment paper into a rectangle about 11.5 inches by 17 inches.

Spread the chilled pastry cream filling on half of the dough lengthwise. Evenly sprinkle the chocolate chips on top of the filling.

Fold the dough in half lengthwise, gently flipping the side without filling over onto the filled side.

Use a large oiled knife to cut the dough horizontally into 10 pastries (you can use a ruler if you want to make them an even thickness; each will be slightly over 1 inch thick).

Transfer the pastries to the prepared baking trays. Cover the trays with plastic wrap. Let them rise at room temperature until the dough is puffed, about 30 minutes. Meanwhile, preheat the oven to 350F.

Once the pastries are assembled and doing their last 30 minute rise, make the sugar syrup.

Combine the ingredients in a small saucepan over medium heat. Bring to a boil, swirling the pan to help the sugar dissolve, and then let it boil for 1 minute.

Remove from the heat and let the syrup cool to room temperature.

Lightly brush the top of each pastry with eggwash.

Bake the pastries until they’re golden, about 22 to 25 minutes at 350F.

As soon as the pastries are out of the oven, brush the cooled sugar syrup on top. The pastries should be hot and the syrup should be cooled for it to absorb properly.

Enjoy!