In a large bowl, whisk together flour, Parmesan cheese, chopped rosemary, salt, and pepper. Cut in the cold butter until the mixture resembles coarse crumbs. Gradually add ice water, mixing until a dough forms.

Form the dough into a disc, wrap in plastic, and refrigerate for 15 minutes.

Preheat oven to 375°F (190°C). On a lightly floured surface, roll out the dough very thinly, about 1/16 inch thick. The thinner the dough, the crispier the crackers will be.

Cut the dough into desired cracker shapes using a knife or pizza cutter. Transfer to a baking sheet lined with parchment paper. Brush lightly with olive oil.

Bake for 8-12 minutes, or until golden brown and crispy. Baking time may vary depending on thickness.

Let cool completely on a wire rack before serving. Crackers will crisp up further as they cool.