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Lemon Blueberry Cake with Lemon Frosting — Fresh, Bright & Perfect for Spring

Lemon Blueberry Cake — three-layer lemon cake sliced to reveal blueberry-studded crumb and lemon curd filling, topped with lemon mascarpone frosting and fresh berries.
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Bright, tender lemon cake layered with juicy blueberries and a whipped mascarpone–lemon filling — this Lemon Blueberry Cake bakes up moist and fluffy thanks to an oil-based batter. Sandwiched with lemon curd and finished with a light mascarpone whipped frosting, it’s a perfect showstopper for spring gatherings or birthdays.

Ingredients

Scale

For the cake

  • 2 cups granulated sugar
  • ½ cup vegetable oil
  • 3 large eggs
  • Zest and juice from 2 lemons (you’ll need about ¼ cup juice)
  • 1 teaspoon lemon or vanilla extract
  • ½ cup light sour cream (or plain yogurt)
  • 2½ cups all-purpose flour
  • 3 teaspoons baking powder
  • 1 teaspoon salt
  • 1 cup buttermilk (or milk with a splash of vinegar)
  • 9 oz fresh blueberries, rinsed and dried
  • 2 tablespoons all-purpose flour (for tossing the berries)

For the frosting & filling

  • 16 oz cold mascarpone cheese
  • 2¼ cups heavy whipping cream
  • 1 cup powdered sugar
  • 1 teaspoon pure vanilla extract
  • 1 jar (10 oz) lemon curd

Instructions

Make the cake

  1. Preheat oven to 350°F (175°C). Grease three 8-inch round pans, line the bottoms with parchment, and optionally add bake-even strips.

  2. In a large bowl, whisk together sugar, oil, eggs, and extract on medium speed until the mixture lightens slightly. Scrape the sides as needed.

  3. Stir in lemon zest, lemon juice, and the sour cream until combined.

  4. In a separate bowl, whisk flour, baking powder, and salt.

  5. Add half the dry mix to the wet bowl, then pour in half the buttermilk; mix on low until just combined. Repeat with the remaining dry mix and buttermilk. Avoid overmixing.

  6. Toss the blueberries with the 2 tablespoons of flour, then fold them gently into the batter. Reserve a few berries to press on top of each pan if you like.

  7. Divide batter evenly among the three pans (roughly 1 2/3 cups per pan). Top with the reserved berries. Bake 20–23 minutes, rotating pans halfway, until a toothpick inserted near the center comes out clean. Cool completely on racks.

Bold tip: If you want flat, even layers, invert the top layer so its bottom faces up when assembling.

Make the mascarpone whipped frosting

  1. Chill your mixing bowl and whisk for several minutes. Place the cold mascarpone in the bowl and beat on medium-low, then slowly stream in the heavy cream so the mascarpone loosens.

  2. Increase speed and whip until soft peaks form. Add powdered sugar and vanilla; mix briefly on low to combine, then whip on high until stiff peaks. The frosting should be light but stable.

Bold tip: Work with cold mascarpone and chilled cream for the best texture.

Assemble the cake

  1. Level the cakes if needed. Place the first layer on your board. Pipe or spoon a layer of mascarpone frosting, then spread half the lemon curd inside the frosting ring.

  2. Add the second layer and repeat: frosting ring, then the remaining lemon curd. Top with the final cake layer (invert it for a flatter top if desired).

  3. Apply a thin crumb coat, chill briefly, then finish covering the cake with remaining frosting. Smooth with an offset spatula or leave a slight rustic texture.

  4. Pipe rosettes or swirls on top if you like, and garnish with lemon slices and extra blueberries. Refrigerate the finished cake.

Bold tip: Don’t recycle frosting that contains crumbs back into your final batch — keep the finish clean.

Notes

  • Substitutions & swaps
    • Swap sour cream for plain non-fat Greek yogurt if that’s what you have.
    • Make quick buttermilk by adding 1 tablespoon vinegar to 1 cup milk; let sit a few minutes.
    • Use raspberries or blackberries instead of blueberries for a twist.
    • Frozen berries may work, but add them frozen and skip the flour toss.
  • Storage & make-ahead
    • Bake the layers ahead, cool fully, wrap tightly in plastic and store in the fridge or freezer.
    • Frost the cake the day you plan to serve it; mascarpone frosting is best fresh.
    • Keep the assembled cake refrigerated for up to 2 days in an airtight carrier.
    • You can freeze unfrosted layers for about a month; thaw in the fridge before decorating.
  • Quick notes & FAQs
    • Why toss berries in flour? It helps keep fresh blueberries from sinking to the bottom of the layers.
    • My cake domes — help! Trim with a serrated knife or use bake-even strips next time.
    • Can I make this dairy-free? You can try plant-based swaps, but results will vary.
    • Safety: Because the frosting contains dairy, keep the cake chilled when not serving.

Nutrition

Find it online: https://irmacooks.com/lemon-blueberry-cake-with-lemon-frosting/