Place the cranberries and sugar in a food processor and pulse for about 1 minute. The cranberry pieces should be fairly small - if the pieces are still quite large, process them a little longer.

Using a hand or stand mixer, combine the butter and sugar/cranberries until they're well mixed. Add the vanilla and mix again. Add the flour, a little at a time, and continue to mix until well-combined. The dough will generally not stay together while mixing, and will instead form many small balls or clumps.

Preheat and over to 350° F (175° C).

Form the dough into small circles and flatten into patties by hand or, for a more uniform appearance, by pressing them into a small measuring cup. Variation: Make mini cookies by measuring a tablespoon of dough, forming it into a ball, and place a deep thumb-print in the middle of the now-flattened ball.

Space the cookies out by about 5-7 cm (2-3 inches) on a cookie-sheet. Bake for 10-15 minutes, or until the bottoms are golden brown and the centers are fairly firm. Baking time can vary depending on your oven and the colour of your baking sheet, so keep an eye on the cookies. Variation: Bake the mini cookies for 8-10 minutes, or until golden brown on the bottom. The cookies will flatten out as they cook and the thumb-print portion will rise and settle, leaving a fairly flat cookie with a slight raised rim around the outside.

Set the cookies aside to cool for about 10 minutes, then set up a double boiler/bain-marie (this doesn't need to be fancy - a small metal pot floating in a water-filled saucepan will work fine). Heat the water to a low simmer, but don't boil. Place the white chocolate in the dry inner bowl and melt, stirring to speed up the process.

Place the crushed pistachios in a small, shallow bowl beside the stove.

Once the white chocolate is melted, roll the individual cookies in the melted white chocolate to cover the rims. Roll the warm chocolate in pistachios, and set the cookies aside on a rack to cool (I personally like them refrigerated, but this isn't strictly necessary). Variation: Place a dollop of white chocolate in the middle of the small cookies, then turn them over and dip them in the crushed pistachios. Set aside to cool.