Preheat the oven to 180 degrees celsius
Using a serrated knife, slice the crossiants in half horizontally.
Dip the croissants fully in the sugar syrup and let any excess syrup fall off then place onto a baking tray lined with baking paper.
Using a spoon or piping bag, fill the croissants with the pistachio frangipane filling. Making sure to leave some for the top. This is to fill like a sandwich.
Chop the chocolate and place a few pieces into each croissant for the chocolate filling
Close the croissants and place a tablespoon of the pistachio filling on the top of the croissant and sprinkle with some chopped pistachios
Place the croissants on a baking tray and place in the oven for 15-20 minutes until the filling is baked and no longer runny.
Leave to cool slightly before eating warm or you can cool completely and store in an airtight container and will last for 1-2 days.