01 -
Preheat oven to 177°C. Line the bottoms of two 20 cm round cake pans with parchment paper and lightly grease the sides.
02 -
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
03 -
In a large mixing bowl or stand mixer, beat the butter and granulated sugar until light and fluffy. Add vegetable oil and eggs, mixing until incorporated. Scrape down sides of the bowl as needed. Add vanilla extract and milk, mixing until smooth.
04 -
Gradually add the dry ingredients to the wet mixture, stirring until batter is fully combined. Divide the batter evenly between the prepared pans.
05 -
Bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean. Cool in pans for 5 minutes, then invert onto a wire rack to cool completely.
06 -
Preheat oven to 177°C. Spread flour for crumb topping on a parchment-lined baking tray and bake for 5 minutes. Let cool. In a bowl, whisk baked flour and powdered sugar. Cut in cold butter using a pastry cutter, forks, or hands, until fine crumbs form. Mix in lemon zest and vanilla extract. Refrigerate until firm, about 1 hour.
07 -
Whip the heavy whipping cream to stiff peaks and set aside. In a separate bowl, mix mascarpone cheese, powdered sugar, lemon zest, and lemon juice until creamy. Gently fold the whipped cream into the mascarpone mixture. Chill filling until required.
08 -
Place one cake layer on a serving plate. Reserve 180 ml of the filling. Spread the remaining filling evenly over the first layer. Place second cake layer on top. Cover the top and sides with the reserved filling. Gently press crumb topping onto the surface and sides of the cake for finish.
09 -
Dust with additional powdered sugar if desired. Refrigerate leftovers for up to 3 days for optimal freshness.