Step 1Sift the flour, sugar, baking powder and salt into a mixing bowl.
Step 2Cut the butter in quarters lengthwise, then slice it into the bowl in 1/4-inch-thick chips. Toss the chips until separated and coated with flour.
Step 3With your fingertips, rub the butter into the flour until the mixture has the texture of coarse meal. Keep your hands above the mixture while you're working to prevent the butter from melting (your palms are warmer than your fingers) and to keep the dough airy and light.
Step 4Beat the whipping cream and yolk together, make a well in the flour and pour in the cream mixture. Blend the liquid into the flour with your fingertips until the dough sticks together; it will be very wet. Turn onto a floured board and pat into a round.
Step 5Now the fraisage--the smearing that brings the dough together better. With the heel of your hand, smear walnut-sized pieces of dough across the work surface for 6 or so inches. Scrape up the heap, press all of the pieces together and pat them into an even 1/2-inch thick round. You can wrap the dough in foil and refrigerate it for a day or two, or proceed at once. (If you're chilling the dough, bring it back to room temperature before beginning the next step.)
Step 6Sprinkle a pastry board or work surface with flour. Roll the dough out to an even 11-inch round, rolling in one direction, then lifting the pin and giving the dough a quarter turn as needed to make a circle (never roll back and forth). Fold the dough in half, brush off any flour, then lift it up and brush off the flour beneath. The dough will be very tender; handle it very gently. If it keeps breaking, knead flour a tablespoon at a time into the dough so that it remains tender but can be lifted up without breaking.
Step 7Center the folded round above a 9 3/8-or 9 1/2-inch two-piece tart pan or a tart ring set on a rimless baking sheet. Unfold the dough and, without stretching, let it fall into place in the ring. Coax it down to fit snugly against the corners. Smooth out any air bubbles.
Step 8Fold the sides down to touch the bottom. Cut off any excess dough even with the rim. Press all around the sides with a fingertip, simultaneously sealing and fluting and making the sides 3/4-inch high.
Step 9Cover the shell and refrigerate from 1 hour to 1 day.
Step 10The shell for this tart will be fully baked. Heat the oven to 350 degrees. Lay a square of parchment or wax paper in the shell and fill with 3 cups pie weights (dried beans are good). Weights keep the dough from bubbling up. Gently press the weights down into the corners and up against the sides over the rim. Bake the shell until the rim is golden, 25 minutes.
Step 11Lift out the paper and weights and return the shell to the oven. Bake until the bottom is lightly golden, about 12 to 15 minutes--check every 2 to 3 minutes and prick with a fork if the pastry bubbles up. Remove from the oven. Cool a shell in a two-piece tart pan in the pan; a shell baked in a ring can be slid off the pan onto a cooling rack. Unmold the shell. If it is in a two-piece pan, set it on a sturdy can and let the rim drop down. Use a spatula to gently nudge the shell off its base and center it on a platter. If using a tart ring, slide the shell off the cooling rack onto the platter and lift off the ring.
Step 12The shell can be baked up to 3 days in advance and kept in a cool dry place, not the refrigerator.
Step 1Cut the pomegranates in half between blossom and stem ends. Ream them on a juicer, then gather the spent seeds into a damp cloth and squeeze out every drop of juice. Strain and measure 1 cup.
Step 2Follow the manufacturer's directions on the pectin box to make elderberry jelly, using the 1 cup pomegranate juice, the lemon juice and sugar.
Step 3After skimming off the foam, use the jelly immediately or pour it into a clean hot glass storage jar, cover and refrigerate up to 2 weeks. Makes 1 2/3 cups.
Step 1Shake the sugar, flour and cornstarch together through a sieve into a mixing bowl. Add the egg and whisk until thick and smooth, about 1 minute.
Step 2Bring the milk to a boil in a small saucepan. Slowly whisk 1/3 of the milk into the egg mixture, then whisk the egg mixture back into the pot. Whisk over medium heat until the custard begins to bubble, then whisk for 1 minute.
Step 3Remove from the heat, pour through a sieve into a bowl, whisk in the almond extract, then blend in the almonds. Lay wax paper on the surface of the cream to prevent a skin from forming. Cool before adding to the tart shell, or cover and refrigerate up to 2 days.
Step 4If the Pomegranate Jelly has set, melt it in a saucepan over low heat, whisking to break up lumps. Pour 1/3 cup into the shell and brush it over the bottom and up the sides for a moisture barrier.
Step 5When this jelly has set, smooth the Frangipane Cream into the shell.
Step 1Add enough water to the sugar to make 1 quart, stirring until the sugar dissolves, then pour the syrup into a 3-to 3 1/2-quart saucepan.
Step 2Peel the pears and cut in half lengthwise. With a small sharp knife, make a V-cut to trim out the cores. Drop the halves into the syrup as you go.
Step 3Bring the syrup to a boil over high heat, reduce the heat to low and simmer until the pears test tender with a thin skewer, 10 to 20 minutes. Skewer them and lift each out as it is ready.
Step 4You can keep the pears in the syrup, covered and refrigerated, up to 3 days. If using right away, cool them before adding to the tart.
Step 5Lift the pears from their syrup and pat thoroughly dry. Lay them on the cream layer, starting with a row of rounded bottoms against the sides, thin edges pointing toward the center; finish with a small pear in the center. For help in lifting and moving pears, use a thin skewer.
Step 6If the pomegranate jelly has set, melt it over lowest heat, whisking until smooth. Spoon about 1/4 cup over the pears and cream, covering them completely but steering clear of the pastry rim.
Step 1Toast the almonds in a dry skillet over medium heat until golden, about 5 minutes. Sprinkle the almonds around the outer edge of the tart in a 1 1/2-inch border. Strew pomegranate seeds over the almonds.