leftover pie/tart dough (I used the cookie-like pate brisee, but standard piecrust will make for a nicely flaky variation)
cardamom seeds, pounded to not-too-big bits in a mortar and pestle
pistachios, finely chopped
egg, beaten with a pinch of salt and splash of water/milk (optional)
On a lightly floured countertop, roll out your leftover dough to a rectangle that is about 5 inches high, and 1/4-inch thick (the length needed to achieve these dimensions will vary based upon how much dough you've got). Sprinkle the dough with a generous sanding of sugar, then the cardamom seeds and pistachios to your taste (the cardamom seeds are fairly strong, so don't go too nuts with those). Then roll up the dough like a jelly roll, tightly, making sure the end seals. Wrap the dough tightly in waxed paper or plastic wrap, and place in the refrigerator to chill for about half an hour.
When the dough is almost finished chilling, preheat your oven to 400° degrees Fahrenheit. Line a cookie sheet with parchment paper, or just grease it, and set aside.
Take your chilled log of dough, and place it on a cutting board. With a sharp knife, slice the dough into 1/4-inch pinwheels. Transfer to your prepared cookie sheet, and repeat with remaining dough. If desired, brush with the egg wash, and sprinkle with additional sugar. Bake until lightly golden, ~10-12 minutes. Let cool, then pack for your picnic.