Place 12 tablespoons cold butter (diced), ⅔ cup powdered sugar, and 2 egg yolks in bowl of food processor fitted with blade. Pulse until combined but still speckled with butter.

Add 2 cups all-purpose flour and run machine just until dough comes together when pinched between fingers. Turn dough out onto large piece of parchment paper, knead a few times to bring together, and pat into disc shape.

Wrap well in parchment and chill for 30 minutes.

Preheat oven to 350°F with rack in center. Remove dough from fridge and let rest on counter for 15 minutes.

Sprinkle flour on work surface and over surface of dough. Roll out dough with rolling pin to approximately 12-inch circle.

Transfer dough carefully to 10-inch tart pan with removable bottom, pressing lightly so it sits snugly against bottom and sides of pan. Prick bottom of shell all over with fork. Place whole pan onto baking sheet.

Place piece of parchment paper over shell, making sure to cover edges. Spread plenty of dried beans or pie weights over parchment, covering whole bottom of tart shell.

Bake for 15 minutes, then remove parchment and beans.

For optional egg wash, beat 1 egg and 1 tablespoon water together with fork in small bowl. Brush shell with egg wash.

Return shell to oven for additional 15 minutes or until completely golden brown. If edges start to color too much, cover lightly with foil. Remove from oven and cool completely before filling.

In medium saucepan, combine 12 ounces cranberries, 1 cup granulated sugar, and ¾ cup water or orange juice. Set over medium-high heat. Once mixture begins to boil, turn down to low and simmer for 10 minutes.

Remove from heat and let cool for 5 to 10 minutes. Transfer mixture to high-powered blender and blend on high for 1 to 2 minutes or until completely smooth. Pour mixture through fine-mesh sieve set over bowl, using spatula to press it through.

Add smooth cranberry mixture back to pot along with 3 large egg yolks and 1 whole egg. Whisk until completely combined. Place pot back on stove over medium heat and continue to heat and whisk constantly for 5 to 10 minutes or until mixture thickens and coats back of spoon.

Remove from heat and stir in 6 tablespoons unsalted butter (cut into small cubes) until completely melted and incorporated. Pour curd into cooled tart crust, spreading evenly to edges.

Refrigerate for at least 3 hours until set. Before serving, garnish with sugared cranberries, whipped cream, fresh rosemary sprigs, or orange slices as desired.