The Queen of Tarts

I thought a nut crust would complement the astringent cranberry filling more than plain pastry, and almond seemed like a good choice since I could enhance its flavor with the nut’s sweet, perfumed extract. So I stirred almond flour together with melted butter, sugar, salt, and almond extract; pressed the dough into a tart pan; and baked it in a 350-degree oven. It was rich and beautifully golden—but so fragile that it crumbled apart when I sliced the finished tart. Plus, some of the curd (a placeholder recipe for now) had seeped through to the pan, indicating that I needed something to bind up the crumb. Both flour and cornstarch worked nicely, so I chose the latter to keep the shell gluten-free.

Tangy, luscious curd is usually made by heating citrus juice (lemon is classic) with sugar, eggs, and butter until the mixture turns thick and glossy. When the curd will be used as a filling rather than as a spread, flour or cornstarch is added to thicken it to a sliceable consistency. It’s then strained to ensure a satiny‑smooth texture, transferred to a tart or pie shell, and baked until it’s fully set.

Cranberry curd, however, is typically made using the whole fruit, including its pectin-rich flesh and skin. Pectin is a potent gelling agent, so the filling doesn’t need the usual number of eggs (six or more per ½ cup of juice) or as much of the flavor‑dulling, starchy thickeners to make it sliceably firm. (Any curd made with citrus juice alone, which contains relatively little pectin, requires more thickeners.) So I ran a bunch of tests, simmering a pound of berries with sugar and water, buzzing the syrupy mixture in the food processor, and heating it again with varying amounts of yolks and cornstarch (plus butter for silky richness). I found that just three yolks and 2 teaspoons of cornstarch provided all the thickening help my curd needed (see “Cranberry’s Secret Weapon: Pectin—and Lots of It”).

But there were a couple other advantages to making curd with cranberries that I hadn’t anticipated. For one thing, I didn’t need to pour the fruit puree back into the saucepan and heat it with the yolks and cornstarch to ensure that it solidified and gelled; the cranberry puree was a piping-hot 180 degrees, so I could add the thickeners directly to the food processor and let them cook in the puree’s residual heat. The other perk was that the berries’ abundance of pectin tightened the curd so effectively that there was no need to bake the filling in the tart shell; it was perfectly set by the time it cooled to room temperature.

The only problem I ran into was cosmetic: As it cooled, the curd developed an unattractive skin—a dry barrier that forms when water evaporates and proteins and sugar concentrate near the surface. Short of pressing a sheet of parchment over the curd, which would wreck its appearance when I pulled it off, I couldn’t prevent a skin from forming. But I had an idea for how to get rid of it before I even transferred the filling to the tart shell: After processing in the eggs and cornstarch, I left the mixture to cool in the processor bowl. When a skin spread over its surface and the temperature dropped to 125 degrees—cool enough that little further evaporation would occur—I processed the puree again (adding the butter first for efficiency’s sake), obliterating all signs of the skin. I strained the filling, poured it into the baked shell, and left it to fully cool. When I tried a bite, it was uniformly silky from top to bottom.

Rich, billowy whipped cream piped into a pretty design would be perfect for topping my tart, but since it doesn’t hold its shape for very long, I’d have to pipe it just before serving. Then I had an idea: Why not make use of the pectin in the filling to help stabilize the whipped cream? It wouldn’t take much, since the calcium in dairy also helps strengthen pectin. And that way, I could pipe it well in advance of the meal. I reserved 2 tablespoons of the curd before pouring the rest into the tart shell. Once the tart had cooled, I whipped the reserved puree with a cup of heavy cream and piped the faintly rosy mixture into a simple yet elegant pattern around the filling’s perimeter.

With that, the tart was perfect. I savored its three contrasting elements: the crisp, golden, nutty crust with sweet, floral overtones; the satiny magenta filling full of sharp, fruity flavors; and the velvety whipped cream that tempered the whole thing. When the holidays roll around, join me in giving cranberries a stunning breakout moment. You’ll be glad you did.