Rhubarb Cake

The Recipe: Is your rhubarb as pretty as can be this year? I can't get enough of it! Here's the rhubarb cake recipe I've been making for years and years, simple and rustic with "just enough" sugar and plenty of rhubarb. Enjoy!

The Conversation: How to choose the right pan for cutting a recipe in half for "half a cake" when a recipe is written for a 9x13 pan.

Rhubarb Cake ♥ KitchenParade.com, simple and rustic, less sweet to really taste rhubarb's wonderful 'sour'.

Real Food, Fresh & Seasonal, a Summer Classic. Weeknight Easy, Weekend Special. Rave Reviews.

Less Sweet for Great "Rhubarb Sour"

When rhubarb comes round, I’m like a new kitten with fresh catnip, I can’t keep my paws off it! Missouri rhubarb is especially beautiful this year and this is a favorite way to show it off. The recipe is a forever-favorite, simple and rustic and for taste, less sweet too. So many rhubarb cakes are teeth-aching sweet. This one lets rhubarb’s great “sour” come through!

Cake Math aka Pan Equivalents

Except for special occasions, a 9x13 cake is just too big around here. A piece or two, that’s all we need. So many times, I bake "half a cake" – adapting a 9x13 recipe for half a recipe.

To bake half a 9x13 cake, what pan should you choose?

Choose an 8x8 pan or a round 10-inch baking pan. Both have roughly half the surface area (64 square inches) of a 9x13 (117 square inches).

The reverse works too. If your brownie recipe fits an 8x8 pan, double the recipe to fit a 9x13. Cool, eh?

If you can, avoid a 9x9 pan, even though it “sounds” just an inch bigger. A 9x9 pan’s surface area is 81 square inches, that’s a full 20% bigger. That said, this Rhubarb Cake fits into a 9x9, the cake just isn’t as tall because it’s spread across 20% more surface area.


Rhubarb Cake Made the List!

Rhubarb Cake ♥ KitchenParade.com, simple, rustic rhubarb cake, less sweet to really taste rhubarb's 'sour'.


Hands-on time: 20 minutes
Time to table: 1 hour
Makes 1 9x13 cake, easily divided in half for an 8x8
  • 1/2 cup (1 stick, 113g) salted butter, room temperature
  • 1-1/4 cups (250g) brown sugar
  • 1 large egg (1 egg works for a half cake too)
  • 1 teaspoon vanilla
  • 1 cup low-fat buttermilk (see ALANNA's TIPS)
  • 2 cups all-purpose flour, fluffed to aerate before measuring or 250g (see TIPS)
  • 1 teaspoon baking soda
  • 3 cups rhubarb, cut in half-inch pieces (save a few pieces for the top, see TIPS)
  • 1/4 cup (50g) sugar
  • 2 teaspoons cinnamon (see TIPS)
  • Few pieces rhubarb

Heat oven to 350F/175C. Spray a 9x13 pan (full recipe) or 8x8 or 10-inch round pan (half recipe).

CAKE With an electric mixer, cream butter and sugar on medium speed until light and fluffy. Add the egg and combine well. Add the buttermilk and combine well. Add the flour and baking soda, mix in just until combined.

With a spatula, turn in rhubarb. Transfer to baking pan.

TOPPING Mix the sugar and cinnamon together in a small bowl. Sprinkle across the top. Insert a few pieces of rhubarb across the top.

BAKE Bake for 30 – 35 minutes until the cake begins to pull away from the pan’s edges and a knife inserted in the center comes out clean.

COOL Let cool until ready to serve. Keeps two to three days.

ALANNA’s TIPS The extra pieces of rhubarb on top are all show-biz, just to tantalize people with color. But don’t be tempted to add more than 3 cups rhubarb, the cake gets too soggy. This cake calls for buttermilk, I use both grocery store buttermilk or Homemade Buttermilk. But I’ve also substituted both low-fat sour cream and low-fat Greek yogurt, thinned a bit with milk to match the consistency of buttermilk. To my taste, all all-purpose flour gives better texture in this Rhubarb Cake than 50% whole wheat or even 100% whole wheat pastry flour. I’m a broken record on this point: Penzeys Cake Spice and Baking Spice blends turn a good cake into a great cake. Just make a 1:1 substitute for cinnamon. Rhubarb Cake can go bad sitting on the counter so if it’s not eaten on the first day, cover and refrigerate.
NUTRITION INFORMATION Per 32 (small) squares or 16 (larger) pieces: 98/196 Calories; 3/6g Tot Fat; 2/4g Sat Fat; 14/29mg Cholesterol; 71/142mg Sodium; 16/32g Carb; 1g Fiber; 9/19g Sugar; 1/3g Protein. WEIGHT WATCHERS POINTS WW Points 2/4 & PointsPlus 3/5 & SmartPoints 5/9 & Freestyle 5/9 & myWW green 4/9 & blue 4/9 & purple 4/9 Sorry, people. Weight Watchers says rhubarb isn't a freestyle "free" ingredient, a mistake in my mind. What's the difference between rhubarb and pumpkin? Both of them get used (mostly) in sweet things. This recipe has been "Alanna-sized" with reductions in fat and increases in color, nutrition and flavor from extra rhubarb and spices.
Adapted from a circa 1980s Iowa church cookbook.

Rhapsody in Rhubarb: More Favorite Rhubarb Recipes

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Upside-Down Rhubarb Cheesecake How to Make Rhubarb Jelly & Jam in Just One Hour Strawberry Rhubarb Cobbler
~ more rhubarb recipes ~
from Kitchen Parade

~ Straight-Up & Perfect Rhubarb Pie ~
~ Custard with Rhubarb Sauce ~
~ Strawberry Rhubarb Smoothie ~
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from A Veggie Venture, my food blog

Shop Your Pantry First

(helping home cooks save money on groceries)

~ buttermilk recipes ~
~ rhubarb recipes ~

~ All Recipes, By Ingredient ~
~ How to Save Money on Groceries ~

Kitchen Parade is written by second-generation food columnist Alanna Kellogg and features fresh, seasonal dishes for every-day healthful eating and occasional indulgences. Quick Suppers are Kitchen Parade favorites and feature recipes easy on the budget, the clock, the waistline and the dishwasher. Do you have a favorite recipe that other Kitchen Parade readers might like? Just send me a quick e-mail via recipes@kitchen-parade.com. How to print a Kitchen Parade recipe. Never miss a recipe! If you like this recipe, sign up for a free e-mail subscription. If you like Kitchen Parade, you're sure to like my food blog about vegetable recipes, too, A Veggie Venture. If you make this recipe, I'd love to know your results! Just leave a comment below.

© Copyright Kitchen Parade
2013, 2019 & 2020 (repub)

Alanna Kellogg
Alanna Kellogg

A Veggie Venture is home of "veggie evangelist" Alanna Kellogg and the famous asparagus-to-zucchini Alphabet of Vegetables.


  1. Great tips on converting pan sizes! And a wonderful cake - rhubarb has terrific flavor, and I need all the new recipes I can find for it. We rarely bake rhubarb into a cake, but should - sounds great. Really excellent post - thanks.

  2. I love rhubarb too! This cake sounds fantastic! Love the cinnamon sugar topping.

  3. Alanna,
    Thanks so much for the pan size conversion tips! I found a recipe calling for a boxed cake mix and an 11x9 inch pan, baked "according to the directions on the box". I couldn't find any boxed mixes that shared 11x9 inch directions, so I just used my 13x9 inch pan and followed those directions.
    With only 3 of us eating, I appreciate smaller sizes. (Though I am providing goodies to my neighbor for handling lawn care for the strip between our houses.)
    I'm crossing my fingers that I'll get my hands on rhubarb this season. Thanks!

  4. Janna on Pinterest11/03/2022

    My family liked it especially because it wasn't overly sweet.


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Thank you for taking a moment to write! I read each and every comment, for each and every recipe. If you have a specific question, it's nearly always answered quick-quick. But I also love hearing your reactions, your curiosity, even your concerns! When you've made a recipe, I especially love to know how it turned out, what variations you made, what you'll do differently the next time. ~ Alanna