Rhubarb Cake with Spiced Sugar Topping

Nov 18, 2024

A seasonal soft rhubarb cake with a spiced sugar topping.

Serve with yoghurt or cream as a dessert or pudding, or slice and have in an airtight container to serve with a cuppa.

I posted this recipe many years ago on my Instagram page, and was reminded of it when I ran into a follower in the supermarket. She was raving about the cake and I new I just had to make again and share the recipe in a printable version.

The Irresistible Charm of Rhubarb Cake

Rhubarb cake is more than just a dessert; it’s a slice of nostalgia wrapped up in a tender, seasonal sweet-tart bite. Whether enjoyed as a humble family recipe or elevated as the star of a gourmet dessert spread, this cake holds a unique place in the hearts of those who’ve experienced its charm.

A Fruit That Isn’t Quite Sweet

This vegetable (yes, vegetable!) with vibrant red stalks and tangy flavour finds its perfect counterpart in the sugar of a well-made cake. Its natural tartness contrasts beautifully with sweet, buttery batter, creating a flavour profile that’s evenly balanced.. Every bite is a reminder of the rhubarb’s ability to shine in desserts despite its earthy origins.

A Nostalgic Treat

For many, rhubarb cake is tied to cherished memories. Perhaps it was a grandmother who first introduced the tangy dessert at Sunday dinners, or a friend who shared their family’s secret recipe on a cozy rainy afternoon.  For me it was the latter.  I was given a version of this recipe by a friend who I worked for many years ago.  They lived in one of New Zealand’s most spectacular spots and one bite of this cake – takes my back to the shores of lake Whakitipu.

The aroma of rhubarb baking—a mix of caramelising sugars and tart fruit—is enough to transport anyone back to warm kitchens and familiar faces and great laughter.

Simple Pleasures with Sophisticated Flair

Rhubarb cake is both simple and sophisticated. It doesn’t rely on fancy techniques or extravagant ingredients; it shines with its inherent flavours. Yet, when served warm with a dollop of whipped cream or a drizzle of vanilla custard, it becomes a dessert worthy of the most refined tables.

So, the next time rhubarb is in season, and you find yourself drawn to its jewel-like stalks, remember that a cake is waiting to be baked—a cake that brings with it not just flavours, but stories, warmth, and joy.

Growing rhubarb is a rewarding experience, as this hardy perennial plant is low-maintenance and can provide fresh, tangy stalks for years with proper care. Here’s a guide to get you started:

Tips on how to grow rhubarb

Rhubarb thrives in a sunny location with well-draining, fertile soil. While it can tolerate partial shade, full sun helps it grow robust and flavourful stalks.

  • Use rich, well-draining soil with a slightly acidic to neutral pH (6.0-7.0).
  • Use a mix pf compost or well-rotted manure before planting for nutrients.

Planting Rhubarb

  • When to Plant: Early spring or autumn is ideal.
  • What to Plant: Rhubarb crowns (dormant roots) are the easiest to grow, though seeds are also an option (they take longer to mature).

Steps to Plant:

  1. Dig a hole about 12 inches deep and wide for each crown.
  2. Mix in compost or aged manure with the soil.
  3. Place the crown with the buds facing upward, about 2-4 inches below the soil surface.
  4. Space crowns 3-4 feet apart to allow room for growth.

Watering and Mulching

  • Keep the soil consistently wet but not waterlogged, especially in the first year as plants establish roots.
  • Apply a layer of mulch to retain moisture and suppress weeds.

Feeding Rhubarb

Feed rhubarb with compost or a balanced fertilizer (like 10-10-10) in early spring and again in late summer after harvesting. Avoid over-fertilizing, as this can reduce stalk production.

Harvesting Rhubarb

  • Wait until the second growing season to harvest, allowing the plant to establish itself.
  • Harvest in spring and early summer.
  • Grasp the stalk near the base, twist gently, and pull. Avoid cutting stalks, as this can damage the plant.
  • Never harvest all the stalks at once; leave at least a third to allow the plant to regenerate.

Care and Maintenance

  • Winter Dormancy: Rhubarb dies back in winter. Cover the crowns with mulch or straw to protect them from frost.
  • Divide Crowns: Every 5-6 years, divide the crowns in early spring or autumn to rejuvenate the plant and prevent overcrowding.

Tips for Success

  • Avoid eating rhubarb leaves—they contain oxalic acid, which is toxic.
  • Keep weeds under control to reduce competition for nutrients.
  • If flowers appear, cut them off to direct energy back into the stalks.
  • Rhubarb is resilient and forgiving, making it great for beginner gardeners!

Growing rhubarb is a long-term investment, but once established, it will reward you with delicious stalks for pies, jams, and cakes for decades!

Rhubarb Cake with Spiced Sugar Topping

A seasonal soft rhubarb cake with a spiced sugar topping.
Prep Time15 minutes
Cook Time45 minutes
Servings: 8
Author: Philippa Cameron

Ingredients

Rhubarb Cake

  • 1 ½ cups brown sugar (300 grams)
  • 120 grams softened butter
  • 2 eggs added one at a time
  • 1 tsp vanilla extract
  • 2 ¼ cups all-purpose flour (335 grams)
  • 1 tsp baking powder
  • 1 cup sour milk to make: mix 2 Tbsp white vinegar into 1 cup milk
  • 1 ½ cups chopped rhubarb (200 grams)

Spiced Sugar Topping

  • ½ cup brown sugar
  • 1 tsp cinnamon

Instructions

  • Preheat your oven to 180°C (350°F). Grease and flour your chosen cake tin (a ring tin or square tin both work well).
  • In a large bowl, cream together the brown sugar and butter until light and fluffy.
  • Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
  • Sift in the flour and baking powder, then gently fold into the wet mixture.
  • Stir the sour milk into the batter until combined.
  • Fold in the chopped rhubarb.
  • Pour the batter into your prepared cake tin and spread evenly.
  • In a small bowl, mix the brown sugar and cinnamon for the topping. Sprinkle evenly over the batter.
  • Bake in the preheated oven for 45 minutes, or until a skewer inserted into the center comes out clean.
  • Allow the cake to cool in the tin for 10 minutes before transferring to a wire rack. Serve warm or at room temperature, on its own or with a dollop of cream.

Notes

  • A ring tin makes this cake visually appealing for special occasions, while a square tin is ideal for cutting into easy-to-serve slices.
  • Store leftovers in an airtight container for up to 3 days.