For the Cardamom-Honey Syrup: In a saucepan over medium heat, bring all ingredients and 1 kilogram water to a boil. Once boiling, remove from heat and cover with plastic wrap. Let steep 30 minutes at room temperature. Once infused, strain mixture and let cool completely over an ice bath. Transfer to an airtight container and reserve.

For the Pistachio Frangipane: In a Vitamix blender, pulse pistachios, salt, sugar, and almond flour, working in batches if needed, until well combined and a flour-like consistency is achieved. Transfer mixture to the bowl of a stand mixer fitted with a paddle attachment. Add butter and mix on medium speed until combined. Add in remaining ingredients and mix until just combined. Transfer to an airtight container and refrigerate.

For the Blueberry Compote: In a saucepan over high heat, combine all ingredients and cook until blueberries begin to break down. Using an immersion blender, blend mixture until slightly smooth, allowing for some texture with the macerated blueberries. Reduce heat and cook until mixture reaches 220°F, stirring occasionally. Once a jam-like consistency is achieved, remove from heat and cool over an ice bath. Transfer to an airtight container and refrigerate.

To Assemble and Serve: Heat oven to 325°F. Brush croissant slices with 10 grams Cardamom-Honey Syrup. Pipe 40 grams Pistachio Frangipane in an even layer on the bottom half of the croissant. Top with 45 grams Blueberry Compote, making sure to keep the Blueberry Compote within the border of the Pistachio Frangipane. Sprinkle with a few fresh blueberries and close sandwich. Transfer to a silpat-lined sheet tray. Bake 25 minutes, or until golden and warmed through. While still hot, brush the top of the croissant with additional Cardamom-Honey Syrup. Dust with powdered sugar and serve warm.