Elizabeth’s Lunar Rhubarb Cake
This lunar rhubarb cake is a thing – do you know of it? It has made the rounds of Canadian kitchens for decades and generations, far before the internet and Pinterest made it easier to share, back when great aunts and neighbours scribbled down the formula for that cake they always make that’s so good. Everyone seems to remember this.
It’s called lunar cake because its surface resembles the pocked surface of the moon, only in this case it becomes irregular and uneven because of the fruit and buttery brown sugar that sinks into the top. (Any fruit will work here – I love these recipes that you can use no matter what’s in season. I already can’t wait for plums.) I’d heard of it but never made one, thinking it was the same sort of fruit-topped cake I’d made dozens of versions of, but when it popped up in the new cookbook by Lindsay Anderson and Dana VanVeller, whose lives I would quickly adopt if I could just dial back 20 years or so, who hopped in a car and ate their way across Canada and then compiled their journey in FEAST: An Edible Road Trip, I knew I had to give it a go. (Also, I’m still trying to use up last year’s epic stash of frozen rhubarb before this year’s crop starts to spring from the ground.)
Spoiler alert: this is much better than any like-minded cakes I’ve baked in the past. Of course Elizabeth Baird knew what she was doing when she took it out and brushed it off for the masses back in 1989.
Confession: I didn’t follow Elizabeth’s instructions directly. Partly because I didn’t want to thaw and drain my frozen rhubarb – typically I just add it to batters frozen, and I didn’t want to lose all that flavourful juice.
And then I neglected to stir said rhubarb into the batter, thinking it went over the surface and sunk in. But once I had spread the batter into the parchment-lined pan, I didn’t want to scoop it out again in order to stir in the rhubarb – I spread it out on top and pressed it in a bit with the back of my spatula, and it worked just fine. I think I’d do it that way again, even knowing that the original recipe called for stirring it in. I think it might even look more lunar this way, too.
The finished cake looks plain, but it’s more intensely buttery and – I don’t want to say sweet, because that can be off-putting and one-dimensional – but more crunchy-topped and caramelized than a typical, straight-up cake. It’s not gooey, but verges on it – served warm, with ice cream, it’s one of the best things I can think of doing with rhubarb. (Also – I love a cake that you don’t have to decorate.)
The book, by the way, is loaded with great tales of Canadian culinary adventures, with stories, histories and recipes from some of my favourite food people from coast to coast. It’s the kind of book I want to absorb all of, and keep propped by my bed just to browse through. It celebrates Canadian cuisine through fresh eyes, with foods you associate with Canada (Nanaimo bars! butter tarts made the right way, with currants!) and new flavours inspired by regional ingredients. (And yes, I even got to contribute a recipe for barley pancakes with blueberry syrup!)
This cake though. It’s going to be in heavy rotation around here.
Elizabeth’s Lunar Rhubarb Cake

Preheat the oven to 350F.
In a large bowl, beat the butter and sugar until pale and creamy, about 3 to 4 minutes. Beat in the egg and vanilla.
Put the rhubarb into a bowl - Elizabeth says if it's frozen, to thaw and drain it, but I used frozen and kept it frozen - and sprinkle over a spoonful of the flour, shaking to coat the rhubarb. Put the rest of the flour into a small bowl or measuring cup and stir in the baking soda and salt. Add to the butter mixture in three additions, alternating with the buttermilk in two.
Spread the batter into a parchment-lined 9x13-inch baking pan and sprinkle with the rhubarb. Press the rhubarb down with the back of your spatula to help it sink in a bit. (I did this because I missed the stirring it into the batter part - you could do that instead, if you like.)
In a small bowl, mix together the brown sugar, cinnamon and butter with a fork and/or your fingers, and sprinkle the mixture over the top of the cake. Bake for 45 minutes, or until deep golden and the cakey parts are springy to the touch. Elizabeth says a toothpick inserted into the centre will come out clean, but I think that's debatable depending on where the sunken bits are - if you test this way, go for a spot near the middle that's clear of rhubarb, because the finished cake is particularly dense and sticky.
Let cool or serve warm, with vanilla ice cream. Serves 10.
Ingredients
Directions
Preheat the oven to 350F.
In a large bowl, beat the butter and sugar until pale and creamy, about 3 to 4 minutes. Beat in the egg and vanilla.
Put the rhubarb into a bowl - Elizabeth says if it's frozen, to thaw and drain it, but I used frozen and kept it frozen - and sprinkle over a spoonful of the flour, shaking to coat the rhubarb. Put the rest of the flour into a small bowl or measuring cup and stir in the baking soda and salt. Add to the butter mixture in three additions, alternating with the buttermilk in two.
Spread the batter into a parchment-lined 9x13-inch baking pan and sprinkle with the rhubarb. Press the rhubarb down with the back of your spatula to help it sink in a bit. (I did this because I missed the stirring it into the batter part - you could do that instead, if you like.)
In a small bowl, mix together the brown sugar, cinnamon and butter with a fork and/or your fingers, and sprinkle the mixture over the top of the cake. Bake for 45 minutes, or until deep golden and the cakey parts are springy to the touch. Elizabeth says a toothpick inserted into the centre will come out clean, but I think that's debatable depending on where the sunken bits are - if you test this way, go for a spot near the middle that's clear of rhubarb, because the finished cake is particularly dense and sticky.
Let cool or serve warm, with vanilla ice cream. Serves 10.
Cakes looks really Good!!!!
I pulled out my frozen rhubarb and discovered strawberries with them, so made a strawberry-rhubarb cake. Delicious! Took an hour to cook in my oven.
OH YUM.
This post reminded me to check the bottom of my freezer for any forgotten gems. Score! I salvaged a 2 cup bag of huckleberry goodness that may have never seen the light of day otherwise. This recipe was the perfect use for the berries on a drizzly Sunday night. Thanks Julie!
Huckleberries! Yes! They’d be perfect!!
YUMMMMMMMMMMMMMMMMMMMMM! This is absolutely delicious. I did it the way you did, and it was sosososo yummy. Whipping cream on top is wonderful but absolutely not necessary. This cake needs no topping or accompaniment. Thanks SO much, Julie!
Right?? Isn’t it amazing? So glad you tried it!
Made this cake today. Best cake ever…just perfection, used 3 cups of rhubarb. Thanks for the recipe Julie.
This cake is really good Julie. I had a slight recipe adjustment as I thought I had frozen buttermilk in my freezer and it turned out to be eggnog so that is what went in the cake. Mine didn’t look quite as ‘lunar’, but it tasted just great with that scoop of ice cream.
That sounds delicious!
I’ve been eating and making this cake for 50 years! It’s a Manitoba staple! I use sour milk, 2 heaping cups of rhubarb, and less sugar. I often add pecans or walnuts in the topping. The best cake ever served warm with ice cream. Or warm with milk for breakfast! Oh yes!
A Manitoba staple.. love it!!
Baking it this morning for Easter brunch. Added a touch of cardamom to the batter and topping — smells incredible.
Oh yes… perfect for Easter brunch!
Made this cake with raspberries. Delicious!! Already thinking of all the other fruit I can use. Will be making this again and again and again.
Ooh, that would be delicious!!
Frozen raspberries?
I am not generally a fan of this type of cake, but this recipe is outstanding. The texture of the cake is light yet decadent. The flavours balance beautifully. I did add more than two cups of rhubarb, and added freshly-grated nutmeg to the dry ingredients. I cannot wait to try this with every gorgeous Niagara soft fruit, as each season comes.
So glad to hear it – and yes, it would be fab with just about any soft fruit!
I make this cake ALL the time… we live it! But….. as I sit here with one in the oven, I realize I did not coat my rhubarb with flour…. any ideas what to expect when out comes out of the oven???
OMG I have been making this cake for 30 years & my mom had it in her repertoire long before. It is such a simple cake & it tastes delicious. It makes my mouth water right now & I have made at least 4 cakes this spring/summer. Great for potlucks & family dinners. it really doesn’t need anything else but it is to fine for warm with vanilla bean ice cream. A Manitoba staple indeed!
This is the best use of rhubarb ever. Made this for a second time today. Perfect every time.
So amazing, isn’t it? I just harvested another armload – last one before the frost hits – and I may just bake another cake.
Have been making this for years – never knew it was called Lunar Cake – we call it Grandma’s Old School Rhubarb Cake – one of those recipes handed down 3 generations.
Amazing – so many old recipes go by different names!
This, according to my family, is the best cake I’ve ever made. It was gone in one day and will be in regular rotation from now on.
I am going to try this cake! I have nice red rhubarb in the freezer from last year and now this year’s crop is growing fast! I am just wondering about the 1 1/2 cups of sugar .. could it be reduced a bit? Has anyone tried it with reduced sugar? thanks!
You could absolutely get away with using less sugar! I’d cut it back to a cup to start?
Served this alongside fruit salad for Fathers Day dinner. Easy and delicious. Thank you for another fantastic recipe Julie!
Yay!
Just made this cake with my first harvest of rhubarb and a bit of fresh strawberries. My result turned out to be more gooey than cake – still good, but not that pretty for company. Plus it’s a little too sweet and buttery for my usual tastes. That said, it definitely will not go to waste!
THANK YOU FOR THIS RECIPE, IT SOUNDS LIKE THE ONE MY MOM MADE, SHE HAS BEEN GONE FOR 20 YEARS i THOUGHT I HAD THE RECIPE, BUT MISPLACED IT. OTHER RECIPES DIDNT SEEM LIKE THE SAME RECIPE SHE HAD. THIS SOUND JUST LIKE IT. THANKS SO MUCH FOR THIS RECIPE
Oh that’s so great to hear Michelle!! xo
Love this! I have been making this cake pretty much the same as written since my kids were small. They are now 46 & 49 and both have birthdays in June. This is the cake they ask for as adults any time we get together & I ask what they would like me to make for dessert. I am patiently waiting for my rhubarb to be big enough to pick & make this cake… I like it better made with fresh rhubarb, but maybe making it while the rhubarb is still frozen like you suggest would work well… I don’t like draining off all the lovely juices! We are in Ontario up near Algonquin Park and things were a bit slow to get started here this year… hopefully by next week! Thanks for this walk down memory lane!