The base directions Line a half sheet pan with parchment or Silpat. Set a rack in the center of the oven, and preheat to 325F.
In the bowl of a stand mixer, cream butter and sugar together until smooth and creamy. Add salt, zest and vanilla and cream until well-combined. Mix in the eggs, one at a time, scraping the bowl as necessary. Mix in the yolk. Add the self-rising flour and mix until just combined. Fold in the dried cranberries, white chocolate chips, and crystallized ginger until evenly distributed. Using an off-set spatula, spread the dough evenly in the prepared pan. Bake for 10 minutes. Rotate the pan and continue to bake until the base is golden brown and fairly firm, for an additional 10-12 minutes more. Remove from the oven and let cool on a rack.
The Frosting In the bowl of your stand mixer fitted with the whisk attachment, whip cream cheese until light. Add the sugar, salt, and orange zest. Mix on low speed until the sugar is incorporated and then whip on medium-high speed until light. Whip in the lemon juice. Now Frost and Finish Once the bars have cooled, spread the frosting in a thin layer with an offset spatula. Don’t be too concerned with being neat at the very edges since you will be trimming them.
Evenly sprinkle on the cranberries. In a microwave-safe bowl, heat the white chocolate chips and oil together in 20-second bursts at medium power, stirring in between, until melted. Scrape into a zip top bag. Snip off a tiny corner and drizzle the white chocolate in a cross-hatch pattern over the berries. Refrigerate for an hour. Using a pizza wheel, trim the edges off the bars to make an even rectangle. Cut vertically into thirds and horizontally into fourths.
You will end up with 12 squares. Cut each square diagonally in half to make 24 triangles. These are dessert size. Cut each triangle diagonally in half again for a total of 48 triangles. These are cookie-sized.