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Rhubarb Cake with Warm Butter Sauce

Rhubarb cake baked with diced rhubarb until golden and tender, then finished with a warm butter sauce that pours over each slice. Moist, homestyle comfort food with a glossy vanilla sauce for a cozy warm dessert.
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Prep Time 20 minutes
Cook Time 45 minutes
cooling 10 minutes
Total Time 1 hour 15 minutes
Servings: 12 servings
Course: Dessert
Cuisine: American
Calories: 420
Ingredients Equipment Method Notes

Ingredients
  

For cake
  • 2 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 butter sauce
  • 1 cup sugar
  • 0.5 cup heavy cream
  • 0.5 cup butter
  • 1 tsp vanilla extract

Equipment

  • 1 sheet pan

Method
 

Bake the rhubarb cake
  1. Preheat the oven to 350°F and grease a 9x13-inch baking pan for easy release.
  2. Whisk together all-purpose flour, sugar, baking soda, and salt in a mixing bowl until evenly combined.
  3. Mix buttermilk, vegetable oil, eggs, and vanilla extract in a separate bowl until smooth and uniform.
  4. Pour the wet mixture into the dry ingredients and stir just until combined to keep the crumb tender.
  5. Fold in the diced fresh rhubarb until evenly distributed through the batter.
  6. Pour the batter into the prepared pan and bake at 350°F for 40-45 minutes, until the top is golden and a toothpick comes out mostly clean.
Make the butter sauce and serve
  1. Combine sugar, heavy cream, and butter in a saucepan and bring to a boil over medium heat, stirring constantly.
  2. Boil the sauce for 3 minutes, then remove from the heat.
  3. Stir in vanilla extract to finish the sauce and keep it warm.
  4. Cool the cake for 10 minutes after baking so slices set up, then serve warm with hot butter sauce poured over individual servings.

Notes

For clean slices, cool the baked cake 10 minutes before cutting, then rewarm sauce slightly if it thickens. Refrigerate leftovers covered for up to 3 days; warm individual portions in the microwave and pour sauce back over. Freezing is not recommended because the rhubarb texture can soften after thawing. If you want a dairy-light swap, use half-and-half for the heavy cream and a reduced-fat butter substitute for the sauce, noting the sauce may be slightly less glossy.