In a bowl, whisk together the flour, sugar, and salt. Add the butter and use your fingers to work it into the dry ingredients until it is crumbly. Use a fork to mix in the egg yolk and water. The dough should start to come together. If dry, add a little more water. If too wet, add a little flour.

Dump the dough onto a floured surface and shape it into a ball. Press the dough into a greased 9-inch tart or springform pan with your fingers, being sure to spread it firmly and evenly across the pan and slightly up the sides. Put the pan in the freezer for 20 minutes for the crust to firm up before baking. Meanwhile, preheat the oven to 425 degrees.

After 20 minutes, take the pan out of the freezer and use a fork to make pricks across the bottom of the dough. Cover the pan with a piece of foil and press down against the crust. Pour pie weights in a single layer on top of the foil, then put the pan in the oven to bake for 12 minutes. After 12 minutes, turn the oven down to 350 degrees and take the foil and pie weights off the crust. Bake another 12 minutes or until the crust is golden and just starting to brown around the edges.

Take the crust out of the oven and immediately add 4 ounces of white chocolate onto the crust. Let this sit for about 5 minutes, then use a small spatula to spread the now melted white chocolate across the crust in an even layer. Put the crust in the fridge to cool while you make the filling.

In a small pan, combine the cranberries, sugar, salt, and orange juice. Place the pan on the stove over medium-low heat and bring to a boil. Lower the heat and allow the cranberries to simmer for about 10 minutes. Process the cranberries and liquid until smooth with an immersion blender, stand blender, or food processor. Take a spoonful of the puree and whisk it into the egg yolks until combined. Whisk this back into the rest of the puree, along with the cornstarch, until smooth.

Allow the filling to cool for about 30 minutes in the fridge. It should still be warm, so stir in the butter until melted and then puree one final time. Pour the cranberry filling into the tart crust. Put the tart in the fridge for a couple of hours or until it has firmed up a bit. Melt the remaining white chocolate and drizzle it over the top however you like. Serve.