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Gooey Cake Bars: Blackberry Swirl with White Chocolate Buttercream

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Ingredients

Scale

BLACKBERRY PRESERVES- or feel free to use store-bought

  • 6 oz blackberries, mashed
  • 3/4 c powdered sugar
  • 2 tsp corn starch
  • 1 tsp vanilla

CAKE BARS

  • 1 box white cake mix
  • 1 small box of vanilla pudding mix
  • 1/4 c water
  • 3/4 c vegetable oil
  • 2 eggs

FROSTING (if you’re not doing detailed decorations, half this recipe)

  • 2 sticks of butter, softened
  • 1/2 c white chocolate, melted and slightly cooled. I used Ghirardelli white melts.
  • 4 c powdered sugar
  • 3 tbsp heavy cream
  • 1 tsp vanilla

DECORATING

  1. Purple gel coloring- I like this brand
  2. Eras Collection sprinkles from Sprinkle Pop

Instructions

PRESERVES:

  1. In a small pot, mix together the blackberries, powdered sugar, and cornstarch. Bring to a boil, stirring constantly.
  2. Continue to cook for about 1 minute until thickened, then remove from the heat and stir in the vanilla.
  3. Let cool

CAKE BARS:

  1. Preheat the oven to 350 degrees.
  2. In a medium bowl, combine the cake mix, pudding mix, water, oil, and eggs. Spread it into a 13 x 9 pan sprayed with baking spray.
  3. Drop the blackberry preserves onto the cake, scattering them throughout the whole pan. Use a pointed knife and swirl the preserves through the batter.
  4. Bake for 30 minutes and then let them cool completely. They should be golden brown on the edges and a bit gooey in the center. Move them to the fridge for at least 30 minutes, ideally longer. This will give them more of a “fudgy” texture.
  5. In a mixing bowl, beat the butter until smooth. Add in the white chocolate and mix. Add in half of the powdered sugar and mix until combined. Then the cream, vanilla, and rest of the sugar and beat until smooth.
  6. If desired, tint the buttercream several shades of purple. I used a regular purple shade, a pinky-purple shade, and a slightly darker shade of purple. Put dollops of the regular purple and pinky-purple onto the cake. Using an offset spatula, spread them so that they have a marble effect.
  7. Put the slightly darker purple shade in a piping bag with a 1M tip. Pipe rosettes/swirls, mini rosettes/swirls throughout the cake. Finish with stars. I only used this one tip, but feel free to use others. Place the sprinkles and butterflies throughout the cake. Serve immediately. Store in the fridge and bring back to room temp if eating later on.

 

Notes

Offset spatula here

Piping bags here

1M tip here