You know day cakes. They're the cakes your mom or your grandmother would make in the days that people would "drop by" the house. An unexpected knock on the door, followed by a warm welcome, exclamations of surprise, cordial sentiments and genuine friendliness, small talk, neighborhood news.

Day cakes are more austere, less flashy than, say, a birthday cake or other elaborate dessert for a true occasion. They tend to be less sweet. They lean vanilla-ward, sometimes scented with citrus or rose water, studded with a few nuts or fruit, but largely unadorned. 

There's something inherently old-timey about a day cake. You eat it with an afternoon cup of coffee or tea. Which assumes you have time to stop what you're doing at, well, tea time (or ever). Step away from the computer, put the phone down. Talk to a human. In front of you. Who has that kind of time? And if you did, who else has that time? You know, to share the cake and the coffee and the conversation with? What is the likelihood of two people who know each other and live in close enough proximity to both be near that cake at, say, 3:00 in the afternoon on any given day? My 2018 mind cannot compute.

Day cakes are for a different sort of celebration. A slower one. A quieter one. They're to celebrate the moment you suspect your toddler has the attention span to help you make a whole cake and wait for it to bake without having a meltdown. A Saturday afternoon that's mercifully, miraculously un-scheduled. A once-in-a-blue-moon visit from a friend on a quick layover to somewhere else. Houseguests. Neighbors with new babies. Time spent with a living grandparent. The arrival of rhubarb at the farmer's market after a winter that wouldn't quit.

Basically, a circumstance just special enough to warrant the eating of a little bit of cake on some random afternoon.

And in a way, that feels more special to me, more rare, more serendipitous than the sort of cake that feeds people who come to it by formal invitation. Those cakes may be beautiful and memorable, the focal point of a photo snapped in the moment before blowing out candles. But a day cake is the kind that lodges itself in a family's, a community's collective memory as something that was always around, always offered, always there; sure the fruit might differ from season to season but there's always the cake, plopped onto an old dinner plate and basking in the sun at the back of the photo. Because the cake isn't the subject. Life is.

Notes:

You can be hopeless with cakes and still nail this one. The mess of rhubarb helps distribute moisture all the way through so you can be a bit lax with the baking time, ignoring the beep of the timer while you finish laundry or dinner or that email. The rhubarb itself turns soft and almost custardy; the pieces sunken deeper are barely discernible among the lemon-scented cake, while the pieces up top get wrinkly and rosy.

I adapted this recipe just barely from Luisa Weiss' beautiful book, Classic German Baking. The main tweak is in the butter: I adore high-fat European-style butter, but rarely think to grab it at the store in case I need to make a specific baked good. Most of Weiss' recipes in the book call for this sort of butter, and rightly so - Oma would want it that way. But in the interest of making this a more spontaneous, back pocket sort of cake to whip up when you happen upon rhubarb at the market, I adapted the recipe to use unsalted supermarket butter. If you do happen to have the "nice butter" lying around, use 7 tablespoons instead of 8. 

Finally, I'll echo Weiss' note about the amount of rhubarb: when you add it to the cake just before baking, it will seem like too much and you may be tempted to panic. In fact, though, it's the perfect amount as it will shrink and soften as it bakes. Don't be afraid! 

• 1 pound rhubarb, trimmed
• 3/4 cup plus 1 tablespoon sugar
• 1/2 cup (8 tablespoons or 1 stick) unsalted butter, softened
• 2 eggs
• 1/2 teaspoon vanilla extract
• Zest of half a lemon
• 1 1/2 cups all-purpose flour
• 2 teaspoons baking powder
• 1/4 teaspoon salt
• 1/4 cup whole milk

Preheat the oven to 350F. Line a 10-inch cake pan with a large piece of parchment paper - you'll let the sides hang over to help take out the cake later.

Chop the rhubarb into 1/2-inch pieces, then toss with 3 tablespoons of the sugar. Set aside.

In a medium bowl, sift together the flour, baking powder, and salt. Set aside.

With a stand mixer using the paddle attachment, combine the butter and the remaining sugar (1/2 cup plus 2 tablespoons) at medium speed until the mixture is light and fluffy, about 3 minutes. Add the eggs one at a time and allow to incorporate completely before adding the next egg. Add the vanilla extract and lemon zest, turning off the mixer once they are incorporated.

Beat in half of the flour mixture on low speed (otherwise you'll cover yourself in flour!), then add the milk and continue mixing. Add the remaining flour mixture and beat until just combined.

Pour the batter into the prepared pan, spreading with a spatula to distribute evenly. (Don't be annoyed if your parchment wrinkles at the edges of the pan, it doesn't really make a difference to the finished cake.) Add the rhubarb on top and press it, gently and evenly, into the batter.

Bake for 1 hour, or until the batter has puffed up around the rhubarb and is just beginning to go beyond golden brown.

Cool the cake on a rack for at least 1 hour, or until it's completely cool. Peel off the parchment and place the cake on a plate. Serve in wedges. The cake is even better the next day (just store it covered, on the counter top), but is best finished up then too. 

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