This recipe challenge was a hard one! The theme was “Solstice” and it involved finding a recipe with an astronomical theme. Well then!

But, as you can see, I was successful with my search! Even in acquiring rhubarb, which is currently out of season and I went to about six stores and two farm stands before finding it.

This particular cake is a favorite of our Canadian neighbors and the recipes are often passed down through generations of family members, kind of like biscuits are in the south or Nona’s “gravy” recipe. So there is very few of these recipes available in written form, beyond a stained recipe card in an old relative’s cookbook. But, digging a little deeper, I was able to uncover a recipe written by Elizabeth Baird in a summer cookbook special written by “Canadian Living” in 1981. So even though the written recipe is more recent in a “historical” context, it is still part of a much older oral tradition going back to the 19th century.

Lunar Rhubarb Cake

  • 1/2 cup (125 mL) butter, softened
  • 1 1/2 cups (375 mL) granulated sugar
  • 1 large egg
  • 1 tsp (5 mL) vanilla
  • 2 cups (500 mL) all-purpose flour
  • 1 tsp (5 mL) baking soda
  • 1/2 tsp (2 mL) salt
  • 1 cup (250 mL) buttermilk
  • 2 cups (500 mL) chopped rhubarb (1/2-inch pieces)

Lunar Topping:

  • 1 cup (250 mL) firmly packed light brown sugar
  • 2 tsp (10 mL) ground cinnamon
  • 1/4 cup (60 mL) butter, softened
  1. Line 13-by-9-inch (3.5 L) metal cake pan with parchment paper or butter thoroughly but lightly. Set aside. Chop rhubarb into 1/2-inch pieces.
  2. In a large bowl, beat the butter and sugar until well mixed and fairly smooth. Add the egg and vanilla; beat until smooth.
  3. Set aside 1 tbsp (15 mL) of the flour. Sift together remaining flour, baking soda and salt, or whisk dry ingredients together in a separate bowl. Add to butter mixture alternately with buttermilk, making 3 additions of these dry ingredients and 2 of buttermilk. Toss rhubarb with remaining 1 tbsp (15 mL) flour.
  4. Spoon rhubarb over the batter and fold in.
  5. Scrape batter into the prepared pan, smoothing the top.
  6. To make Lunar Topping: In bowl, mix together sugar and cinnamon. With a fork or pastry blender, work butter into the sugar mixture until crumbly.
  7. Sprinkle topping evenly over the batter. Bake in the center of a 350 F (175 C) oven until the lunar topping is pitted and crusty and a skewer inserted into the center comes out clean, about 45 minutes. Let cool on rack. While you can cover and store the cake for up to 2 days at room temperature, it is best made and served the same day.

So I added the “somewhat softened” butter to the massive amount of sugar. I say “somewhat” because I forgot to pull the butter out till last minute, hoping that being near the preheating oven would give it enough time to soften. It didn’t.

I was successful in whipping the sugar and butter together in the end, with the help of my trusty hand mixer! But it looked to me more like mashed potatoes than fluffy whipped sugar/butter. Though I continued onward and added the large egg and the vanilla and beat them all together.

It’s starting to look like it’s coming together! I felt a bit better at this point.

Then I combined the flour/baking soda/salt together in a separate bowl. I also got the buttermilk set (which isn’t pictured here).

A great tip if you don’t have buttermilk in the house (which I didn’t) but you need it for a recipe (which I did). For every cup of milk add a tablespoon of vinegar to it. Mix it up and set it aside for a few minutes. Works every time!

I then added a third of the flour mixture to the whipped butter/egg/vanilla/sugar mixture, then half the milk, then another third of the flour mixture, then the rest of the milk, and the rest of the flour mixture, mixing it by hand the whole time. You don’t have to do it this way, you can keep using your stand/hand mixer if you want.

I would love to say it was because I wanted to have better control over my batter, or something deep like that. No, it really was because my hand mixer was a bit warm after doing so much butter/sugar beating that I decided to give it a break. And my stand mixer is somewhere in the back of our storage unit.

The batter did come out beautifully smooth, if I do say so myself!

Onto the rhubarb!

It was very elusive, this plant. Not something to look for in July in New England (easier to find at the end of May/beginning of June). But, when I finally did find it, I was so elated I did a happy dance right in the produce aisle much to the delight of my 4 year old son, and to the confusion of other nearby shoppers wondering why this woman was jumping up and down with fists full of rhubarb. But I digress…

A simple wash under some cold water, a dry, and then some not so precise chopping later, I had two cups of rhubarb, ready and waiting.

I will admit here, I forgot to leave aside some of the flour from the batter so I could coat the rhubarb in it. So this was a spoonful of extra flour I added. The flour helps keep the rhubarb from sinking down to the bottom of the batter. It’s great tip for any type of fruit you want to put into cake batter.

So, because the theme of this bake is “forgetfulness”, I had to add the floured rhubarb pieces to the top of the batter, rather than mixing them in before pouring it in the pan. This still worked, as I pressed the pieces down into the batter. At least I remembered to put in the parchment paper (DON’T skip this step! The cake is very sticky!).

So onto the crumble that goes on top! This brown sugar looks very light in this lighting, but I assure you it is brown. And, by this point in the bake, the butter in this bowl was well softened (and much easier to mash up with the sugar and cinnamon).

There! All mixed!

I then sprinkled it (well clumped it) over the top of the rhubarb/batter mixture.

Luckily I remembered to preheat the oven for 350 F. So into the oven it went, for closer to 50 minutes.

50 Minutes Later…

TA DA!!!

I will say the house smelled HEAVENLY. Well if Heaven smells like cinnamon and sugar (which it totally should!).

They say the name of this cake comes from the fact that the sugar melting into the cake batter as it bakes makes these craters, like the surface of the moon. I think that’s a bit of a stretch, but I won’t argue too much because it helps me fulfill my challenge.

The bigger challenge was waiting for this cake to cool so I could cut a piece and try it! (I did try to cut a piece while it was still warm and it completely fell apart. You definitely need to wait till it is completely cool… sadly.)

The Taste Test

Once completely cooled, I cut out a slice while trying to keep the piece together since it was sticking to the sides and bottom of the pan, which luckily were lined with parchment. Hence why they are necessary.

I decided as well to try it with some ice cream because, well, why not!

The first spoonful was quite a surprise, in a very good way. I didn’t realize how sweet the cake would be. Mainly because I knew the rhubarb would be very tart. But the fluffy, light texture of the cake with the bursts of sweet brown sugar and tart rhubarb pieces reminded me of a coffee cake, with rhubarb. And I was totally right in adding a creamy component, in this case vanilla ice cream. It needed it to temper down the sweet tartness.

But I am very happy with how this came out. And the rest has been packed up to bring to my parent’s house this weekend. I know my mother will LOVE this, being as it is a coffee cake with a tart kick to it.

But I will certainly be making this again soon! If I can find fresh rhubarb again…