Combine sifted flour and 3/4 cup plus 2 tablespoons cold butter in the bowl of a food processor; pulse briefly until dough starts to form. Add Parmesan cheese, Gruyere cheese, and salt and process for 1 more minute.
Turn out dough onto a lightly floured work surface and shape into a ball. Wrap in plastic wrap and refrigerate for at least 1 hour.
Preheat oven to 350 degrees F (175 degrees C). Line 2 baking sheets with parchment paper.
Cut off small portions of dough with an ice cream scoop or your hands and flatten with your hands. Place unbaked crackers onto the preheated baking sheet, leaving space between them.
Bake in the preheated oven, rotating the baking sheet halfway, until crackers are lightly browned, 12 to 15 minutes.