Moist Rhubarb Cake Recipe

Moist Rhubarb Cake Recipe

Bake the Moist Rhubarb Cake Recipe for a tender, tart-sweet traybake that’s easy to make and share.

Prep Time20 minutes
Cook Time50 minutes
Total Time70 minutes
Yield12

Ingredients

Instructions

Step 1: Preheat and prepare the pan

Preheat the oven to 350°F (175°C) and lightly grease a 9x13 inch rectangular baking pan so the batter will release cleanly after baking. Use a light coating of butter or a neutral oil and set the prepared pan to the side while you mix—this simple step ensures the final cake keeps neat, straight edges and caramelized corners.

Step 2: Macerate the rhubarb

Place the 2 1/2 cups chopped fresh rhubarb in a small ceramic bowl with 1 cup of sugar and toss to coat. Let this sit while you prepare the batter—the sugar draws out moisture and softens the rhubarb, creating juicy pink streaks that will punctuate the cake and add a pleasantly tart contrast.

Step 3: Sift the dry ingredients

In a separate bowl, sift together 2 cups all-purpose flour, 2 teaspoons baking powder, and 1/4 teaspoon salt. Sifting aerates the flour and evenly distributes the leavening and salt, giving the cake a lighter crumb and consistent rise.

Step 4: Cream the butter

In a large mixing bowl, cream 1/2 cup (1 stick) softened butter until light and fluffy. Beat at medium speed or by hand with a sturdy wooden spoon; the butter should become pale and aerated—this trapped air is part of what keeps the cake moist and tender.

Step 5: Incorporate the egg

Beat one large egg into the creamed butter until fully incorporated and smooth. This step builds structure and helps the batter emulsify so the flour blends without becoming heavy.

Step 6: Combine wet and dry

Alternate adding the sifted flour mixture and 1/2 cup milk to the butter-egg mixture, beginning and ending with the flour mixture. Mix only until combined—stop when you no longer see streaks of flour to avoid overworking the batter; it should be thick, slightly glossy, and ribbon off the spoon.

Step 7: Fold in the rhubarb

Gently fold the macerated rhubarb and any released juices into the batter with a rubber spatula, keeping the chunks intact so bright pink and pale green rhubarb pockets remain visible. The batter becomes speckled with berry-pink streaks and small pockets of fruit—this is the tactile, visual hallmark of the cake.

Step 8: Transfer to the pan

Pour the rhubarb-studded batter into the prepared 9x13 rectangular pan and spread it evenly with an offset spatula, smoothing the top but leaving surface texture so the topping can cling. The batter should reach all four corners and present an even, slightly peaked surface for an even bake.

Step 9: Add the topping

Combine 1/4 cup sugar with 1 teaspoon ground cinnamon and sprinkle evenly over the batter so the sugar-cinnamon crystals sit on top. This topping will caramelize and create a thin, crackly surface during baking.

Step 10: Bake and cool

Bake the pan for 45–50 minutes until the top is golden and a toothpick inserted in the center comes out clean. Remove the pan and cool on a wire rack until warm, then allow to cool completely in the pan so the cake firms and slices cleanly.

Step 11: Slice and serve

Using a sharp knife, cut a rectangular or square slice from the pan and place it on a simple white plate; the slice should retain the straight, rectangular geometry from the pan with slightly caramelized edges and a tender, crumbly interior dotted with pink rhubarb. Serve at room temperature—if desired, gently sift a very light dusting of extra topping sugar over the slice for a subtle sheen and added aroma.

Notes