n a stand mixer with a paddle attachment or in a bowl with an electric mixer, beat together the butter, icing sugar, vanilla and salt until light and fluffy, about 2-3 minutes. Stir in the flour just until combined. Add the chopped pistachios and chopped dried cranberries and mix until combined.
Press dough into a 9-inch round tart pan with a removable bottom (or alternately, a 9-inch round cake pan, lining the bottom with a round of parchment paper). Flatten dough with the palm of your hand to make a smooth surface. Using a sharp knife, score the surface of the dough in to 16 wedges. Prick each wedge with a fork twice. Refrigerate pan with dough until firm, about 30 minutes.
Meanwhile, preheat oven to 300F.
Bake cookies in preheated oven until firm and pale golden, about 45-50 minutes. Remove from oven and let cool for 5 minutes, then, using a sharp knife, cut through the score lines you made before baking, wiping off the blade between each cut. Allow to cool completely in the pan.
Meanwhile, prepare glaze by combining white chocolate chips with cream in a microwaveable bowl. Microwave for 45 seconds. Remove and stir. Microwave in additional 30 second intervals until melted. Stir in icing sugar, adding additional cream if needed to make a glaze that will easily drip off a spoon.
*Note: If you end up with small lumps of solids in your glaze, pour through a fine mesh sieve to remove before dipping.
Tip: Be sure to use a bowl that will allow you to dip the cookies in flat from end to end, so it should be at least 5-inches wide. That said, don't use too big a bowl or your glaze will be too thin a layer and you may bottom-out when you dip).
Prepare your chopped pistachios and chopped dried cranberries and set aside.
Remove cookies from pan to a rack. Holding a cookie by the sides, dip the top of the cookie into the glaze to coat. Hold point side down and allow the excess to drip off. Gently remove any drip at the point end by running it along the edge of the bowl. Place on to rack. Once you've done about 4 wedges, sprinkle those ones with some of the chopped pistachio and cranberry, before the glaze sets to much that they won't stick. I like to sprinkle a bit of the smaller stuff first, sprinkling over the outer 2/3 of the wedge (leaving the narrow end clear). Then sprinkle some of the larger pieces at the wide end. Repeat until you have glazed and sprinkled all the cookies.
Allow to stand until the glaze is set, about 1 hour or pop in the fridge to speed the process up. Store in a flat even layer in an airtight container. These keep well stored at room temperature for about a week. These would also freeze well!
Be sure to read the "Cook's Notes" in the original post, for more tips, options, substitutions and variations for this recipe!