3 cups flour
1/2 teaspoon coarse salt
2 tablespoon sugar
1/2 pound (two sticks) cold unsalted butter, cut into tablespoon-sized cubes
1 cup sour cream
1 teaspoon vanilla extract
1/2 cup sugar
2 teaspoons rosewater
a few dried rosebuds (optional)
scant 2 cups raspberry jam
1 cup chopped pistachios
egg wash of 1 egg beaten with a splash of water
The day before you want to bake, make the rose sugar. In a food processor (you can just use a bowl if you're skipping the rose petals), mix together the sugar and rosewater. Add the rose petals, if using, and blitz until combined. Leave out, uncovered (or partially covered, depending upon your bug situation) overnight, until dry.
At least an hour before you want to bake, make the dough: In a bowl or a food processor, mix together the flour, salt and sugar until combined. Add the butter, and pulse in the food processor or cut with a pastry cutter (or two knives) until it is reduced to bits that are about half the size of a pea. If using a food processor, dump the contents into a bowl at this point. Stir the vanilla into the sour cream. Using a spoon, and then your hands when needed, knead the sour cream and vanilla into the flour mixture until it is well incorporated, and the dough holds together when you squeeze it. Stop as soon as this is possible — do not over-mix. Shape the dough into four chubby disks, cover with plastic and allow to relax in the refrigerator for at least one hour (overnight is fine too).
Preheat oven to 350° Fahrenheit, and line two cookie sheets with parchment or liners (very important, as the molten jam tends to solder them to a pan).
Take a disk of dough out of the refrigerator, and place on a floured countertop or pastry mat. Roll out to a 12" circle, trimming off the ends if needed. This dough is much softer than a traditional pastry crust, so you shouldn't need to let it warm up before rolling. Spread 1/4 of the jam over the round of dough, and sprinkle with 1/4 of the nuts, and a few tablespoons of the rose sugar. Taking a chef's knife or pizza cutter, divide the dough evenly into 16 wedges. Starting from the wide base of each wedge, roll towards the center to form a crescent. Place on your prepared baking sheets, making sure that the tip of the crescent is pinned underneath to prevent the cookie from unrolling.
Take your egg wash, and, using a pastry brush, gently give the cookies a nice slather. Sprinkle generously with the rose sugar. Transfer to the oven, and bake until the filling is bubbling and the crust is just beginning to color, about 30 minutes. Remove to a rack to co