What's kuchen?

A delightful pun on 'What's cooking?' or a perfect transition to explain that kuchen is the German word for cake? I say both. Despite my German heritage, my vocabulary is limited to food (largely Christmas cookies).
Plums are ripe and plentiful right now, so when my dad brought home a bagful yesterday, we both thought 'kuchen'. This isn't strictly a kuchen, but the shortbread crust was very nice! You can do most of the prep the night before, and no messing with pastry-the crust is impossible to screw up.

Plum Tart with Lemon-Shortbread Crust (from Fine Cooking #94)

• 1/3 cup + 1/2 tbsp sugar
• 1 tbsp cornstarch
• 1/4 tsp kosher salt
• 1/4 tsp finely grated lemon zest
• 6 ripe medium black or red plums (about 4 oz. each-mine were smaller so I used 8), pitted and sliced into 16 slender wedges (or as many as you can get)
• 1/2 cup or 4 oz. or 8 tbsp cold unsalted butter, cut into 1/2 inch cubes
• 1 egg yolk
• 2 tsp firmly packed finely grated lemon zest
• 1/2 tsp vanilla
• 1 cup + 2 tbsp all-purpose flour
• 1/4 cup granulated sugar
• 1/4 tsp salt
• Cooking spray
• 2 tbsp plum or apricot preserves

1. In a medium bowl, whisk 1/3 cup sugar with cornstarch, kosher salt and lemon zest. Add the sliced plums and gently toss with your hands to evenly coat. Cover the bowl and refrigerate 1 hour to overnight.
2. Lightly butter the bottom and sides of a 9 1/2 inch fluted tart pan with a removable bottom. Put the butter cubes in the freezer. In a small bowl, whisk the egg yolk, lemon zest, and vanilla. Put the flour, sugar, and salt in the bowl or a food processor (or a regular bowl if no food processor, like me), and pulse a few times to combine. Add the butter and pulse until the mixture is crumbly and mealy, about 25 short pulses (use a pastry cutter if no processor). Add the egg yolk mixture and blend, using long pulses, just until it forms a moist, crumbly mass, about 15 three second pulses. The dough won't come together on its own, but it should hold together when squeezed. Transfer the dough to the tart pan. Dip the bottom of a flat-bottomed cup measure in flour and use it to press the doug onto the bottom and sides of the pan in an even layer (alternatively, use your hands. Or use them first and then the measuring cup to clean things up). Wrap the pan in plastic and refrigerate 1 hour to 1 day.
3. Heat oven to 375˚. Unwrap tart shell and prick the bottom and sides several times with a fork. Spray one side of a piece of parchment paper or foil with cooking spray. Line the shell with the sprayed side down and fill the lined shell with pie weights or dried beans. Set the tart pan on a baking sheet and bake for 20 minutes. Carefully remove the pie weights and liner. Reduce heat to 350˚ and continue baking until the sides and bottom of the shell are golden brown and dry, 10-15 minutes. Cool for about 20 minutes.
4. Drain the plums in a sieve or colander set over a medium bowl for a few minutes. Pour the juice into a small saucepan and bring to a simmer over medium heat. Reduce the heat to low and simmer, stirring occasionally until very thick, about 3 minutes. Scrape into a small bowl and let cool. Next, melt the preserves in the saucepan over medium-low heat until syrupy. Pour the preserves into the tart shell and evenly brush them over the bottom and sides. With a rubber spatula, spread the plum juice over the preserves on the bottom of the shell. Starting at the edge of the shell, arrange the plum slices cut side down and tightly overlapping in concentric circles. If you have more slices, keep tucking them in wherever they fit. You can also pile a few in the center of the tart.
If any juice remains in the mixing bowl, drizzle up to 1 tbsp. over the plums. Discard the rest. Sprinkle the remaining 1/2 tbsp sugar over the plums. Bake the tart directly on the oven rack until the plums are tender when poked with a paring knife and caramelized along their edges (a few tips may even blacken), the crust is a deep golden brown, and any juices look syrupy and bubbly, 40-50 minutes. After you remove the tart from the oven, moisten the plums by dipping a pastry brush into the juices between the plums and brushing any surfaces that look dry.
Cool the tart in its pan on a rack for at least 2 hours before unmolding and slicing with a very sharp knife.