The first rhubarb bars I ever ate were in a kitchen in the Powderhorn neighborhood of Minneapolis, on a Sunday in late May, with the screen door open because Linnea said the lilac out back was finally doing its thing. Linnea was my Airbnb host. She was 72, wore a green apron with a stitched chickadee, and had a kitchen that smelled like coffee and butter at every hour of the day.
I was in town for three nights between a job in Chicago and a friend’s wedding in Duluth. I almost did not take the room. I am glad I did not skip it.
How a Cooking Class Turned Into a Host Kitchen
I had actually booked a 4-hour Scandinavian-American cooking class through a community center near Lake Street, the kind that starts with a chaotic market tour where the instructor walks too fast and everyone loses the group at least once. We made lefse. We made a passable pickled herring. We did NOT make rhubarb bars.
But Linnea found out where I had spent my afternoon, laughed, and said the class had it wrong if they skipped the bars. She pulled a spiral-bound church cookbook off the shelf above her stove. Mount Olive Lutheran, 1978, the spine taped twice. She tapped a page with a flour-dusted finger. We are doing this tomorrow, she said. You are helping.
The Pink Stalks on Her Counter
The next morning her counter had four enormous rhubarb stalks on it, mostly green with pink streaks. I made the mistake of asking if they were ripe enough. Linnea gave me a look. Color does not mean ripe, she said. That is a myth. Green rhubarb tastes the same. She said her own mother grew the green variety on purpose, claimed it held up better in the oven.
She was right, by the way. The research backs her up. Rhubarb color is determined by cultivar, not maturity, and the pale green stalks can be just as flavorful as the deep crimson ones you see on Instagram.
Linnea also corrected me on the leaves. I had picked one up to move it. She slapped my wrist, lightly, and said never, ever. Oxalic acid. Toxic. The stalks only. I have never forgotten that.
What Goes Into It
- 2 cups all-purpose flour, for the shortbread crust
- 1/2 cup powdered sugar
- 1/4 teaspoon salt, for the crust
- 1 cup cold unsalted butter, cubed
- 4 large eggs, room temperature
- 2 cups granulated sugar
- 1/2 cup flour, for the custard
- 1/4 teaspoon salt, for the custard
- 1/4 cup heavy cream
- 1 teaspoon pure vanilla extract
- 4 cups fresh rhubarb, diced into 1/2 inch pieces, leaves discarded
The History Linnea Did Not Bother to Tell Me
I had to look this up later. Rhubarb came to the Upper Midwest with Scandinavian, German, and English immigrants in the 1800s, and the cool climate of Minnesota and the Dakotas suited it almost suspiciously well. It earned the nickname pie plant because it was often the first thing edible to come up out of the spring garden, before any actual fruit was ready.
The bar cookie format itself, sheet-pan style, took off in the mid-20th century through community and church fundraiser cookbooks. Easy to cut, easy to transport, easy to feed a basement full of people after a Lutheran funeral lunch. Which is exactly the cookbook Linnea pulled from. I love a tradition you can trace.
One more thing I learned later. The U.S. classified rhubarb as a fruit in 1947 for tariff purposes, but botanically it is a vegetable. Linnea would have rolled her eyes at that.
Bringing the Rhubarb Bars Home to My LA Kitchen
Back in LA the problem was finding rhubarb at all. It is not a Southern California crop. I had to wait until the Hollywood farmers’ market on Sunday and ask the stand that sometimes drives stuff down from up north. Two weeks of asking. Eventually a man named Curt put four pink-green stalks in a paper bag for me and said good luck.
I made the bars the next morning, kitchen window open, the jacaranda outside dropping purple all over the sidewalk, Nick Drake on the speaker because that is what was already playing and I did not change it. The cast iron was off the stove for once. I needed a 9 by 13 metal pan instead.
The shortbread crust is the easy part. Whisk the dry, cut in the cold butter with a pastry cutter until it looks like sandy crumbs, dump into the pan, press it down hard with the flat of a measuring cup. Bake at 350 for 14 minutes. It should look dry and just barely golden at the corners.
While that bakes, whisk the eggs, sugar, flour, salt, cream, and vanilla into a custard. No lumps. Pat the diced rhubarb dry with a paper towel, a step I skipped the first time and regretted because the bars came out a bit weepy. Fold the rhubarb into the custard. Pour over the hot crust. Push it gently to the corners with a spatula.
Back in the oven for 40 to 45 minutes. The custard should be set around the edges with only a slight wobble in the very middle. Onto a wire rack. Cool an hour. Then, and this matters, into the fridge for at least two hours. Overnight is better. I have tried to skip this. Do not.
Small Things I Have Changed
I add a touch more vanilla than the recipe says, maybe an extra half teaspoon, because the supermarket vanilla in LA is not as punchy as whatever Linnea was using. I also dust the cut bars with powdered sugar right before serving, which she did not, but it photographs better and tastes about the same.
Frozen rhubarb works in a pinch. Thaw it, drain it well, toss it with an extra tablespoon of flour to soak up the water. The texture will not be quite as snappy but you will still have rhubarb bars in November, which counts for a lot.
I prefer them cold, the next day, eaten standing up at the counter with coffee. Linnea would have served them on a plate, with a napkin, like a person. I am not Linnea.
If you make these, send Linnea a thank you in your head. She is the reason this recipe left her church cookbook and ended up on a wooden table in California, getting morning light through the jacaranda. Worth the two weeks of farmers’ market asking. Worth the flight back.
Rhubarb Bars
Ingredients
Equipment
Method
- Preheat the oven to 350 F. Lightly grease a 9x13 inch baking pan or line it with parchment paper, leaving an overhang on two sides for easy lifting.
- Make the shortbread crust. In a large bowl, whisk together 2 cups flour, the powdered sugar, and 1/4 teaspoon salt. Add the cold cubed butter and cut it in with a pastry cutter or two forks until the mixture looks like coarse, sandy crumbs with no large butter chunks remaining.
- Tip the crumb mixture into the prepared pan. Press it firmly and evenly across the bottom with the flat base of a measuring cup, packing it down well so it bakes into a solid layer.
- Bake the crust for 14 minutes, until it looks dry and just barely golden at the edges. Leave the oven on.
- While the crust bakes, prepare the custard. In a medium bowl, whisk the eggs until smooth, then whisk in the granulated sugar, 1/2 cup flour, 1/4 teaspoon salt, heavy cream, and vanilla extract until fully combined and lump-free.
- Pat the diced rhubarb dry with a paper towel to remove surface moisture, then fold it into the custard mixture until evenly coated.
- Pour the rhubarb custard over the hot par-baked crust, spreading it gently with a spatula so the rhubarb is distributed evenly to the corners.
- Return the pan to the oven and bake for 40 to 45 minutes, until the custard is set around the edges, lightly golden, and has only a slight wobble in the very center when the pan is nudged.
- Transfer the pan to a wire rack and cool completely at room temperature, about 1 hour. Then refrigerate for at least 2 hours, or overnight, until the custard is firm and cold.
- Lift the bars out using the parchment overhang and place on a cutting board. Use a sharp knife to slice into 16 squares, wiping the blade clean between cuts. Dust with extra powdered sugar just before serving if you like.