Place the flour, the finely grated cheeses, the diced butter, the salt, and pepper into a large mixing bowl.
Using your fingers, rub and knead the ingredients together until a smooth dough forms.
This can take time—if needed, add a small splash of cold water or a sprinkle of flour to help bring it together.
Wrap the dough and let it rest in the fridge for 30 minutes.
Roll the dough out on a floured surface to about 5mm thick.
Cut into shapes using metal cookie stamps or cutters.
Place the cookies on a baking tray lined with parchment paper or a silicon tray.
In a small bowl, beat the egg to make an egg wash.
Brush it over each cookie.
Decorate with your choice of toppings: chili flakes, rosemary, smoked salt, or other pantry favorites.
Bake in a preheated oven at 180°C (356°F) for about 10 minutes per batch, or until the bottoms are golden.
Let them cool completely before serving.