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Rhubarb Cake with Hot Butter Sauce

Rhubarb cake with butter sauce is a moist, golden dessert studded with diced rhubarb and baked until just set. Warm cake is served with a hot, pourable butter sauce so each slice gets drenched in glossy vanilla goodness.
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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
 

Make the rhubarb cake
  1. Preheat oven to 350°F and grease a 9x13-inch baking pan with a light coating to prevent sticking.
  2. Whisk all-purpose flour, sugar, baking soda, and salt in a mixing bowl until the dry ingredients look evenly combined.
  3. Mix buttermilk, vegetable oil, eggs, and vanilla extract in a separate bowl until smooth and uniform.
  4. Pour the wet ingredients into the dry ingredients and stir until just combined, keeping the batter thick and avoiding overmixing.
  5. Fold in fresh rhubarb pieces so they’re distributed through the batter.
  6. Pour batter into the prepared pan and bake for 40-45 minutes, until the top is golden and a toothpick comes out mostly clean.
  7. Cool the cake for 10 minutes so it slices cleanly and holds its shape.
Make the hot butter sauce
  1. In a saucepan, combine sugar, heavy cream, and butter, then stir to combine and dissolve any sugar clumps.
  2. Bring the mixture to a boil over medium heat while stirring constantly to keep it smooth.
  3. Boil for 3 minutes, then remove from heat to stop further thickening.
  4. Stir in vanilla extract and keep the sauce warm for pouring.
Serve
  1. Serve warm cake with hot butter sauce poured over individual servings so the sauce soaks in right away.

Notes

Pro tip: Dice rhubarb into small, even pieces so they bake through without leaving hard pockets. Store leftover cake covered in the refrigerator up to 3 days; rewarm slices in the microwave before serving and reheat sauce gently until pourable. Freezing is yes for the cake (up to 2 months), but sauce is best made fresh. For a lighter option, use half-and-half instead of heavy cream (the sauce will be slightly less thick).