Blueberry Cake Layers

1. Preheat your oven to 325°F (165°C) with fan and line three 6-inch cake pans with parchment paper.
2. In a bowl, sift together the flour, baking powder, baking soda, and salt.
3. In another bowl, mix the buttermilk with the lemon juice and let it sit for a few minutes.
4. In the bowl of a stand mixer, beat the softened butter and sugar on medium speed for 2–3 minutes, until creamy.
5. Add the eggs, vanilla extract, and lemon zest, then beat for 5 minutes until light and fluffy.
6. Gently fold in the dry ingredients, alternating with the buttermilk mixture, until the batter is smooth.
7. Toss the blueberries in a bit of flour and gently fold them into the batter without crushing them.
8. Divide the batter evenly between the pans and smooth the tops.
9. Bake for 40–45 minutes, or until a toothpick inserted in the center comes out clean.
10. Let cool in the pans for 10 minutes, then turn out and cool completely on a wire rack.

Blueberry Compote

1. Follow my homemade blueberry compote recipe using 1½ cups (200 g) of fresh or frozen blueberries with 1 tablespoon of cornstarch.
2. Cook until thick and jammy, then let cool completely.

Mascarpone Whipped Cream (Filling)

1. In a large bowl, combine cold mascarpone, cold heavy cream, powdered sugar, vanilla extract, and lemon juice or zest.
2. Beat with an electric mixer on medium speed until thick and smooth.
3. Transfer to a large piping bag and keep refrigerated until ready to use.

Mascarpone Frosting (For Outer Layer)

1. Right before assembling, prepare my mascarpone frosting for coating the cake.
2. Fill a piping bag with a small amount for decorating the top.

Assembly

1. Set up your cake space with a turntable and a cake board.
2. Place the first cake layer on the board.
3. Pipe a ring of mascarpone frosting around the edge to hold the filling in place.
4. Spread a thin layer of whipped mascarpone inside the ring, then spoon 1–2 tablespoons of blueberry compote in the center.
5. Add the second cake layer, press gently to level it, and repeat the same steps: frosting ring, whipped cream, and blueberry compote.
6. Place the final layer upside down (flat side up) for a clean top.
7. Apply a thin layer of mascarpone frosting all over the cake (crumb coat) and chill for 20 minutes.
8. Then cover the cake with a thicker layer of mascarpone frosting and smooth it out using a cake scraper.
9. Pipe decorations on top using the remaining whipped cream and add a bit of blueberry compote.
10. Chill the finished cake for at least 1 hour before serving to let the frosting set properly.