Pulse together the gruyere, butter, sea salt, coriander and black pepper until butter and cheese are broken into little bits. Add flour and pulse until ingredients come together. Turn dough out onto a clean countertop and knead lightly to bring it all together. Pat dough into a log about 10 1/2 inches long and 1 1/4 inches around. Wrap dough in plastic and chill for 2 hours, or until very firm.
Preheat oven to 325 degrees. Slice each log into 1/4-inch rounds and bake on parchment-lined sheets until golden brown and firm in the center, about 20 to 25 minutes. Cool completely on a baking rack and serve at room temperature.