Rhubarb Custard Cake.

Late last week we had many sunny, warm summer-like evenings.  On one of them I decided to blop down on an Adirondack chair outside and read the May addition of Bon Appetite with an extra full glass of white wine.  I truly enjoy these calm moments filled with all the simple pleasures life has to offer.

Ben was BBQing and watching playoff hockey, Barkley was begging me to throw his ball, and Chewy was chasing flies & chattering with the birds.  It was the perfect evening.

I love reading and adore flipping through real magazines.  I am not sure what I’d do if the world went totally digital.  There is just something about tearing out pages of recipes you want to try or dog-earring corners of items you want to go back to.  And this recipe was one of them.

Rhubarb Custard Cake.  It looked beautiful, sounded delicious, and seemed pretty easy.  I had everything in the house except for the rhubarb so I simply planned to run to the grocery quickly the next morning and pick some up.  Easy enough.

Fast forward to the next morning, I was stoked to wake and bake!  Yes, I am aware this has two meanings but in my world, it means waking up to thoughts of cupcakes and muffins dancing along in my head.  It means I pop out of bed excited to pour that first cup of coffee and preheat the oven.  It means that I can’t wait to bake my heart out starting at the wee hours of the morning!!


So for the cake, I followed Bon Appetit’s directions to a tee.  However, when it came to the ingredients department, I switched a few things up!  I used RylieCakes' Cake Mix of course and I added in a few extra spices to make it my own :)

I added some cinnamon to the dry mix to start.  I find the sweet-spicy flavor of cinnamon to be irresistible and I absolutely love the smell of it baking away.  I also added some finely diced fresh ginger in with the lemon zest.  I thought this would give a fiery little kick to the sweet custard-like cake.  Plus, both cinnamon and ginger have amazing health benefits!!  So why not?!

While the cake was in the oven I was pondering what to do with the leftover rhubarb…  Should I make Rhubarb Jam?  Curd?  Mousse?  Just eat it plain?  And then I saw the mascarpone in my fridge!  Immediately I knew what I had to do!

I was going to make a Whipped Mascarpone Cream to go on top of the cake and then Rhubarb Compote to go on top of that!  Both ended up being genius ideas!!

For the Whipped Mascarpone Cream, make sure you chill your mixing bowl and whisk attachment.  Do NOT skip this step!!  And when adding your heavy whipping cream, be sure to do so slowly. 

Please note that this recipe calls for “Heavy Whipping Cream”, which means it should be added to the recipe in its liquid state.  If a recipe calls for “Heavy Cream, whipped”, then you would want to whip it first before adding to your recipe.  This concept was quite confusing to me for the longest time so I hope saying something now straightens out any confusion you may have.

Last but not least, do not over whip the Mascarpone Cream.  Just like whipping Heavy Cream, it will begin to curdle if over whipped.  Simply whip until it appears light and fluffy, holds stiff peaks, and has nearly doubled in size.  Yes, I know this is easier said than done!!

For the compote, you seriously just toss everything in a pan, bring it to a boil for 5 minutes and then let it simmer for 5 minutes.  It is nearly impossible to screw up!

Once all components are ready to go, you can assemble your masterpiece!

Using an offset spatula, spread the Whipped Mascarpone Cream over the cake (I did not use all of the cream).  Then I used a wooden spoon to spread the Rhubarb Compote over the cream topping.  Again, I did not use all of the compote.  Your cake will now be ready to serve!

A few notes on serving:

  1. If you do not intend to eat the entire cake in one sitting (or you simply don’t have enough guests to do so), I would recommend just spooning the Whipped Mascarpone Cream and Rhubarb Compote on each serving individually.  If left on the entire cake overnight, the cake will get soggy from the compote.
  2. The cake, compote, and cream can all be made ahead of time.  Feel free to make each component a day or two ahead of your get-together and then on the day of you just need to assemble quickly and serve!
  3. For the leftover cream and compote, we ate it on toast at our house for breakfast with a hot cup of coffee :)  However, the Rhubarb Compote would be PERFECT for pouring over your favorite ice cream and the Whipped Mascarpone Cream would be ideal for dolloping on top of a heaping bowl of fresh berries!!  Just saying…

With Memorial Day Weekend fast approaching, this is the perfect recipe to not only please your guests but to keep your time in the kitchen limited!

Eat, enjoy, and repeat a few too many times while rhubarb is in season :)

Lick the Bowl – You Only Live Once,

Tara Rylie

Rhubarb Custard Cake Adapted from Bon Appetit

(Yield: 10 servings)



  • 5 oz RylieCakes' Cake Mix
  • ¾ tsp baking powder
  • ½ tsp kosher salt
  • 1/8 tsp Saigon Cinnamon
  • 2 large eggs
  • 1 large egg yolk
  • 11.25 oz sugar
  • 2 oz butter, melted
  • 2.15 oz sour cream
  • 2 Tbsp dark rum
  • 2 tsp finely grated lemon zest
  • 0.20 oz fresh ginger, finely diced
  • 8 large stalks of rhubarb
  • QS sparkling sugar


Grease a 9” springform pan with soft butter and then sprinkle with RylieCakes’ Cake Mix.  Preheat oven to 350°F.

  1. In a medium bowl, whisk together Cake Mix, baking powder, salt and cinnamon.  Set aside.
  2. In another medium bowl, whisk together eggs, egg yolk, and sugar until thick and very pale in color.
  3. Whisk in melted butter, sour cream, rum, lemon zest, and fresh ginger.
  4. Add dry ingredients to batter and fold with a spatula until smooth.  Pour into prepared pan.
  5. Arrange rhubarb over batter however you like, trimming as needed. Sprinkle with sparkling sugar.
  6. Bake for 1hr, rotating cake 180° halfway through.  The cake should be golden brown on top when done.  The top will feel quite hard to touch but I promise the center will still be cakey + custardy!
  7. Transfer pan to a wire rack and let cool for 20 minutes.  Then slide a knife around sides of cake to loosen and unmold. Slide cake directly onto rack and let cool completely before adding cream and compote :)

Whipped Mascarpone Cream

(Yield: Approximately 16 oz)



  • 8 oz mascarpone, chilled
  • 2 oz powdered sugar
  • 8 oz heavy whipping cream, chilled
  • 2 tsp vanilla extract
  • 1 Tbsp dark rum


Chill mixing bowl and whisk attachment for at least 30 minutes before whipping.  If you can place your bowl and whisk in the freezer, 15 minutes should do the trick!

  1. Place mascarpone into chilled mixing bowl fitted with whisk attachment.  Add powdered sugar and begin whisking.
  2. Turn speed up to 4/6 and whisk until mascarpone has nearly doubled in size.  It should look like it has “grown” up the sides of the bowl.
  3. Scrape the sides of the bowl and then begin whisking again but this time on low speed.  SLOWLY pour in chilled heavy cream, vanilla extract, and dark rum.  Once it is all incorporated, turn mixer up to 4/6 and whisk until a whipped cream like consistency is formed.  The mixture should hold firm peaks.  DO NOT OVER MIX. 

Rhubarb Compote

(Yield: Approximately 16 oz)



  • 14.75 oz rhubarb, ½” diced
  • 3.5 oz brown sugar
  • 2.25 oz honey
  • 2 oz orange juice


  1. Place all ingredients into a 1.5 QT saucepan. 
  2. Bring to a boil over medium-high heat.  Let boil for 5 minutes.
  3. Then turn heat down to low and let simmer for an additional 5 minutes.
  4. Remove from heat and stir occasionally.  Compote will thicken as it cools.