In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and blue cheese together for 1 minute, or until smooth. With the mixer on low speed, add the flour, rosemary, salt and pepper and mix until it's in large crumbles, about 1 minute. Add 1 tablespoon of water and mix until combined.

Dump the dough onto a floured board, press it into a ball and divide in half. Roll into a 12-inch long log.(Ina said do one roll, but that makes a really big cracker. Mine came out the size of a half dollar coin.) Brush the logs completely with the egg wash. Spread the walnuts in a square on a cutting board and roll the log back and forth in the walnuts, pressing lightly, and distributing them evenly on the outside of the log. Wrap in plastic and refrigerate for at least 30 minutes or for up to 4 days.

Meanwhile, preheat the oven to 350 degrees F.

Cut the log into 1/4" slices with a sharp knife and place the crackers on a sheet pan lined with parchment paper or Silpat. Bake for 22 minutes* until very lightly browned. Rotate the pan once during baking. Cool and serve at room temperature.

*My crackers took longer to cook. At one point I flipped them over so they would dry out a bit. I would say my crackers cooked an extra 6-10 minutes. You can taste one at the end of the cooking time to see if they are done. They do crisp up when cooled.