In a saucepan over medium heat, add syrup ingredients, stir a little then let it boil. When it boils, reduce heat and simmer for 10-15 minutes.
Turn heat off and let it cool down to room temperature, it will thicken as it cools down.
Mix the sugar and the cornstarch in a blender until it has a powdery consistency. That is “confectioners’ sugar”.
Whip the cream with confectioners’ sugar until soft peaks form.
Add the pistachio paste and the mascarpone cheese. Mix very well until incorporated.
In a bowl, combine the dry ingredients well.Add water and mix until everything is well incorporated, cover and let it rest for 30 minutes. You can do this step in a blender.
The batter should be runny and not thick like pancakes.
In a skillet set over medium heat, pour 2 tablespoons of batter.
Cook until the batter has no visible wet spots you will notice bubbles forming on the surface. Do not flip.
Scoop or pipe about a teaspoon of the filling in the middle of the qatayef.
Pinch the edges together sealing them two-thirds of the way. Dip the open side into ground pistachios. Enjoy!