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Three-Layer Rhubarb Cake

For a springtime dessert with a twist, we layer a cardamom-and-lemon-scented batter with jammy rhubarb and a crunchy almond streusel.
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Published Mar. 30, 2021.

Three-Layer Rhubarb Cake

In Scandinavia, the arrival of rhubarb signals the close of a long winter. The prolific perennial is used in pies, crumbles, soups, and jams. It is fermented into wine, and its juice is sipped fresh. Purists even eat stalks raw, dipping them in sugar to quiet their bracing tartness. But perhaps the finest celebration of rhubarb is the making of rich butter cakes that are dotted with chunks of the crimson-green stems, perfumed with cardamom and lemon, and speckled with sugar and crisp almonds.

The treat is a far cry from the rustic rhubarb upside‑down cake I enjoyed as a kid in rural Vermont, where the plants grew wild at the edge of our neighbor’s property. No, the flavor of the Nordic cake is more sophisticated—and the texture more intriguing.

That said, I enjoy the heavy use of rhubarb in the upside-down style, which creates an incredibly appealing compote-like layer atop the cake. So why choose? Instead, I got to work on a culinary mash-up using our Apple Upside-Down Cake (September/October 2009) as a template. That cake is rich with butter, sour cream, and brown sugar, and it would take well to the spice and citrus flavorings.

Having worked with rhubarb a lot over the years, I knew that it would soften quickly in the oven, so I skipped the stovetop parcooking step that the apple cake recipe calls for. I cut a full pound of stalks into long, slender planks; tossed them with melted butter and brown sugar as well as some fruity lemon zest to help balance their slight savoriness (rhubarb is a vegetable, after all); and organized the planks into neat perpendicular stacks to create a geometric arrangement on the bottom of an 8-inch square baking pan. Along with vanilla, I spiked the cake batter with the aromatic upgrades: ground cardamom and lemon zest and juice. I poured the batter on top of the scarlet slices, slid the pan into a 350-degree oven, and baked the cake for about 45 minutes.

A Tasty, Texture-Rich Trio

We not only add a third component to the usual cake and fruit but also turn up the flavors a notch.

After the cake cooled, I turned it out onto a platter. I expected the artfully arranged rectangles to resemble garnet stained glass, but instead I got a different type of stain: The brown sugar that had worked so well with the apples had turned the blushing rhubarb a murky brown. Plus, the rhubarb had wept as it baked, making the crumb soggy. Finally, the long planks were stringy, so they were tricky to cut for serving, never mind eat gracefully.

A handful of fixes really paid off: To start, I abandoned the finicky slices of rhubarb and simply diced the stalks and packed them into the bottom of the pan. This produced an attractive mosaic design with zero fuss. To help preserve the color of the chunks, I swapped the brown sugar for granulated (to keep things simple, I switched to granulated in the cake, too). I also sprinkled in 11/2 teaspoons of cornstarch to help the juices gel during baking.

Rhubarb Rules

Color is cosmetic 

The red color in rhubarb is not necessarily an indication of ripeness; it comes from betalain pigments that vary according to variety and growing conditions. For a more attractive cake, seek out red stalks, but greenish ones will taste good, too.

 

Foil keeps it crisp 

For long-lasting stalks, loosely wrap trimmed rhubarb in aluminum foil and store it in the refrigerator. It will stay crisp for up to two weeks.

The cake now baked up with a fruity, lightly thickened topping. The rhubarb pieces were no longer brown, but their rosy color had still faded a bit, so after the cake cooled, I dabbed on some melted red currant jelly to restore a crimson shine.

Now, what to do with the almonds? Their nutty crunch contrasted nicely with the plush cake and soft compote, but the angular slices looked awkward perched atop the rhubarb layer. My solution was a topsy-turvy one: I arranged the rhubarb in the bottom of the pan, added the batter, and then sprinkled a mix of sugar and sliced almonds on top. Once the cake was baked and inverted, the nuts formed a crispy base.

I was on the right track, but the delicate sliced almonds were hard to notice buried beneath the rest of the dessert. For my next try, I turned the almonds and sugar into a substantial streusel by adding melted butter and flour. The cake baked up with a generous nutty base, and my gastronomic merger was complete.

Rhubarb Upside-Down Cake

For a springtime dessert with a twist, we layer a cardamom-and-lemon-scented batter with jammy rhubarb and a crunchy almond streusel.
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