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Best Ever Easy Rhubarb Cake

Easy rhubarb cake that bakes up as a moist sheet cake with pink rhubarb pockets and a buttery cinnamon crumble topping. A simple dessert with a tender crumb and a golden top—perfect for spring baking.
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Prep Time 15 minutes
Cook Time 45 minutes
cooling 30 minutes
Total Time 1 hour 30 minutes
Servings: 12 servings
Course: Dessert
Cuisine: American
Calories: 330
Ingredients Equipment Method Notes

Ingredients
  

For cake
  • 2.5 cup all-purpose flour
  • 1.5 cup sugar
  • 1 tsp baking soda
  • 0.5 tsp salt
  • 1 cup buttermilk
  • 0.5 cup vegetable oil
  • 2 eggs
  • 1 tsp vanilla extract
  • 3 cup fresh rhubarb, diced
For topping
  • 0.5 cup sugar
  • 1 tsp cinnamon

Equipment

  • 1 sheet pan

Method
 

Prep and bake
  1. Preheat oven to 350°F and grease a 9x13-inch baking pan so the cake releases cleanly after baking.
  2. Whisk all-purpose flour, sugar, baking soda, and salt together in a bowl until the dry ingredients are evenly combined.
  3. Mix buttermilk, vegetable oil, eggs, and vanilla extract in a separate bowl until smooth.
  4. Pour the wet ingredients into the dry ingredients and stir just until combined to keep the cake tender.
  5. Fold in the fresh rhubarb, diced so the batter is studded with pink pieces.
  6. Spread the batter into the prepared pan in an even layer for consistent baking.
  7. Mix sugar and cinnamon, then sprinkle evenly over the batter to create a lightly crunchy, spiced top.
  8. Bake for 40-45 minutes at 350°F until golden and a toothpick comes out clean.
Cool and serve
  1. Cool the cake for 30 minutes before serving so the rhubarb sets and the slice holds together.

Notes

For the most even rhubarb distribution, fold it in gently and spread the batter right to the pan edges. Store covered in the fridge up to 4 days; freeze slices up to 2 months (thaw overnight in the fridge). Dietary swap: use low-fat buttermilk if you want a lighter option while keeping the same texture.