How to Make It
In a medium bowl, using an electric mixer, beat the butter with the confectioners' sugar on medium speed for 2 minutes. Beat in the egg yolk, scraping down the sides of the bowl with a rubber spatula. Using a wooden spoon, stir in half of the all-purpose and bread flours until combined. Mix in the remaining flour to form a soft, sticky dough. Scrape the dough onto a piece of wax paper and form into a flat disk. Wrap and refrigerate until firm, at least 2 hours or overnight.
On a lightly floured surface, cut the cold dough into 1-inch pieces. Using the heel of your hand, knead pieces together until the dough is smooth but still cool, using a pastry scraper or metal spatula to free the dough from the work surface. Roll the dough into a 12-inch-long log and cut into 8 equal pieces. Transfer to a plate, cover with plastic wrap and refrigerate until cold, about 20 minutes.
Line a large baking sheet with parchment paper. Place eight 4-inch-round flan rings or 4 1/2-inch fluted tartlet pans with removable bottoms on the baking sheet. Remove 1 piece of dough from the refrigerator and, on a lightly floured surface, roll it into a 5 1/2-inch round. Ease the pastry into 1 of the tart rings. Using your thumbs, gently but firmly press the dough into the ring, taking care to form a close fit around the base. Using a small sharp knife, trim the dough flush with the rim. Prick all over with a fork. Repeat with the remaining pastry. Freeze the rings on the baking sheet until the pastry is firm, about 15 minutes.
Meanwhile, preheat the oven to 375°. Bake the tartlet shells on the baking sheet until golden, about 12 minutes. (If the dough puffs up, tap it down with the back of a spoon; do not prick it.) Remove the tartlet shells and let cool on the pan. Leave the oven on.
In a small saucepan, bring the heavy cream to a simmer over low heat. In a heavy medium saucepan, cook the sugar over moderately high heat, stirring constantly with a wooden spoon, until melted, about 5 minutes. Swirling the pan occasionally, cook until the sugar is a rich golden brown, about 2 minutes. Immediately whisk the hot cream into the caramel, taking care to avoid splatters; do not let the mixture boil over. Cook, whisking constantly, until smooth. Strain the caramel into a medium bowl. Add the cranberries and almonds and stir to coat completely with caramel.
Place the baking sheets with the tartlet shells on top of another baking sheet (to prevent the bottoms of the tartlets from burning). Mound the filling into the tartlet shells and bake for 25 to 35 minutes, or until the cranberries have burst and the edges of the pastry have browned.
Remove the rings from the tartlets with tongs; if they stick, run a small sharp knife around the tartlet rims and then lift off the rings. Using a metal spatula, carefully transfer the tartlets to a rack to cool slightly. Serve warm or at room temperature.