These crackers are very rich, yet still quite light and crispy. They pair well with soup.
In the bowl of a food processor, finely grind 1/2 cup walnuts. Add flour, salt, pepper, and baking soda; pulse to combine. Add butter; pulse until mixture resembles coarse meal. Add cheese; pulse until dough comes together, about 15 seconds.
Preheat oven to 350 degrees. Transfer dough to lightly floured surface; divide into two equal parts. Using your hands, roll dough into two 1 1/2-inch-diameter logs. Coarsely chop remaining 1/2 cup walnuts; sprinkle over a clean work surface. Roll logs in walnuts. Wrap each log in plastic wrap, and chill until firm, at least 3 hours.
Slice logs into 1/4-inch-thick coins. Transfer to ungreased baking sheet; sprinkle lightly with coarse salt. Bake until centers are firm to the touch, about 15 minutes. Transfer to a wire rack to cool. Store in an airtight container, at room temperature, 3 to 4 days.