Prepare Dough
In a mixing bowl, combine the all-purpose flour, whole wheat flour, powdered protein, sugar, and salt.
Cut in Butter
Add cold, cubed butter and mix until the mixture resembles coarse crumbs.
Add Liquids
Stir in the cold brewed coffee and milk until just combined.
Chill the Dough
Shape the dough into a disk, wrap in plastic, and refrigerate for at least 30 minutes.
Roll and Fold
On a floured surface, roll out the dough into a rectangle. Fold the dough into thirds, like a letter, and roll again. Repeat this process two more times.
Shape Croissants
Cut the dough into triangles. Roll each triangle from the base to the tip, creating a crescent shape.
Prepare for Baking
Place the croissants on a baking sheet lined with parchment paper. Brush with beaten egg for a golden finish.
Bake
Preheat your oven to 375°F (190°C) and bake for 20 minutes or until golden brown.
Cool and Serve
Allow the croissants to cool slightly before serving. Enjoy your fancy breakfast!