Blueberry Buttermilk Cake: A Tender Sheet Cake With Lemony Mascarpone Frosting That Stays Soft for Days

This tender blueberry cake beats dry holiday bakes. The secret to its soft crumb is buttermilk, which keeps the cake moist and tender for several days. A creamy mascarpone frosting is the finishing touch.

The rich frosting with a hint of lemon adds freshness to the cake. Blueberries in the batter are a classic that always pleases. How do you keep the batter light and not heavy?

How do you make a tender blueberry buttermilk sheet cake?

The base is a creamed batter. Beat softened butter with sugar and eggs, then alternate adding buttermilk and flour with baking powder. Fold in the blueberries and bake at 350°F (180°C). Spread the cooled cake with a frosting of mascarpone, butter and sugar.

At a Glance

• Prep time: 20 min
• Baking time: 30 min (plus cooling)
• Servings: 20 pieces (11 1/2×13-inch / 29×33 cm pan)
• Difficulty: Easy
• Calories: about 390 kcal per piece
• Trend: Holiday baking / One pan

Ingredients

Instructions

1. Heat the oven to 350°F (180°C) (conventional, top and bottom heat). Line an 11 1/2×13-inch (29×33 cm) baking pan with parchment paper.
2. In a large bowl, beat the softened butter (1 cup plus 2 tablespoons / 250 g) with the powdered sugar (2 cups / 250 g) and vanilla until pale and fluffy.
3. Add the 5 eggs one at a time. Beat each egg for at least a minute, until it is fully combined with the butter.
4. In a second bowl, whisk the flour with the baking powder.
5. Add the buttermilk and the flour mixture to the egg mixture in 3 additions, alternating. Mix only gently now, with a spatula or on low speed.
6. Gently fold in the lemon zest and most of the blueberries (save a few for the top).
7. Spread the batter evenly in the prepared pan. Scatter the remaining blueberries on top.
8. Bake at 350°F (180°C) for about 30 minutes. Test with a toothpick to make sure the center is baked through. Let the cake cool completely.
9. Frosting: In a bowl, beat the softened butter (1/2 cup plus 1 tablespoon / 125 g) with the sifted powdered sugar (1 1/4 cups / 150 g) until fluffy.
10. Add the cold mascarpone and the lemon juice. Beat only briefly (about 30 seconds), just until the frosting comes together into a firm mass. Be careful not to overbeat.
11. Spread the frosting over the completely cooled cake and chill until set.

Video Recipe

Tips for Perfect Blueberry Buttermilk Cake

• The buttermilk secret: Buttermilk (or kefir) makes the crumb especially tender. It keeps the cake from turning dense and helps it stay soft for several days.
• Sugar in the frosting: The original video uses 300 g (2 1/2 cups) of powdered sugar in the frosting. This version uses 150 g (1 1/4 cups) for a more balanced flavor. If you like very sweet frostings, add more.

Easy Variations

• No-frosting version: The cake is delicious without frosting, simply dusted generously with powdered sugar.
• Other fruit: Use frozen raspberries, red currants or drained apricot pieces instead of blueberries.

Frequently Asked Questions (FAQ)

The cake is best well chilled, so the frosting does not crumble when you cut it. Store it in the refrigerator only.

The recipe is based on a version by Einfache Rezepte, adapted by the We Cook With Love team.

Enjoy! Try more recipes from our kitchen.