Step 1 Heat the oven to 350 degrees. Let the butter sit at room temperature for 15 minutes, until malleable.
Step 2 Place the powdered sugar in the bowl of a standing mixer or a large free-standing bowl. Add the pieces of butter and toss to coat. Using a paddle attachment with a standing mixer, combine the sugar and butter at medium speed, until the sugar is no longer visible.
Step 3Add the egg yolk and combine until no longer visible.
Step 4Scrape down the butter off the sides of the bowl. Add half of the flour, then begin mixing again until the dough is crumbly. Add the remaining flour and then the cream and mix until the dough forms a somewhat sticky mass.
Step 5Flatten the dough into a thick pancake, wrap it in plastic and refrigerate at least 2 hours before preparing to roll out the dough.
Step 6Lightly butter a 9-inch pastry ring or fluted tart pan and place it on a baking sheet lined with parchment paper or a nonstick Silpat pad.
Step 7Once the dough has thoroughly chilled, cut it in half, then cut each piece in half lengthwise. Rotate the dough 90 degrees and repeat, until you have 16 equal pieces. Sprinkle your work surface with a thin layer of flour. Knead the pieces of dough together until it forms one new mass and shape it into a flattened ball. Flour a rolling pin and sprinkle flour again on the work surface underneath the dough. Roll out the dough into a circle one-eighth-inch thick.
Step 8Dock the dough with a pastry docker or prick the dough all over with a fork. Transfer the dough into the ring or tart pan by rolling about a third of it around your rolling pin, lifting it and placing it into the ring. Gently pat the dough onto the bottom and up the sides of the ring. Trim the edges so that they are flush with the top. Put the baking sheet with the ring into the freezer for one hour. Bake 15 to 20 minutes or until lightly browned. Remove from the oven and let cool to room temperature before filling.