Preheat the oven to 300 degrees.

In a stand mixer, stir together the flour, sugar, baking powder, vanilla sugar and anise seeds.

Mix in the 3 whole eggs one at a time. Pour in the orange blossom water, oil, and 2 tablespoons of warm water and continue mixing. The dough should be moist and slightly sticky. Place into a bowl and cover with plastic wrap and refrigerate the dough for at least 10 minutes.

Separate the dough into two balls and place them on a parchment-lined baking sheet. With wet hands, press the balls into long loaves. The dimensions of the loaves should be around 12 inches long by 3 inches wide.

Sprinkle your filling of choice over the loaves and lightly press them into the dough. Fold up the sides and press them together so that the filling is now in the center. Press down to flatten the loaves to be 1 inch thick. Place the baking sheet into the fridge for an additional 30 minutes to set the loaves.

Remove the loaves from the fridge, brush with the beaten egg yolk and sprinkle with sesame seeds.

Bake the boulou for 30 minutes until golden brown.

Remove the baking sheet from the oven and set the loaves aside for about 5 minutes or until they have cooled a bit to the touch and are still warm on the inside. Slice the boulou into ¾-1 inch thick slices and allow the cookies to cool completely. to room temperature.

Serve with a side of orgeat syrup.