01 -
Preheat oven to 175°C. Grease three 20-centimetre cake pans, line with parchment paper circles, grease again, and dust with flour.
02 -
Using a food processor, blend lemon zest with 3–4 tablespoons of granulated sugar until the sugar is vivid yellow and the zest fully incorporated. Alternatively, combine zest and sugar in a bowl and rub together until fragrant.
03 -
In a bowl, mix whole milk, lemon juice, egg whites, and vanilla extract. Set aside.
04 -
In the bowl of a stand mixer, combine cake flour, remaining granulated sugar, lemon sugar, baking powder, and salt. Blend on low speed until even.
05 -
Add softened butter pieces one at a time with mixer running. Continue mixing until the mixture resembles coarse crumbs with pea-sized butter pieces.
06 -
Pour in half the egg white mixture and increase mixer speed to medium-high. Beat until light and fluffy, about 1 minute. Lower speed to medium-low, add the rest of the mixture, and mix until fully combined. Stir a few times by hand to ensure the batter is blended.
07 -
Divide batter evenly between prepared pans, smooth tops, and bake for 18–22 minutes or until cakes are lightly browned and a toothpick inserted in the centre comes out clean. Rotate pans halfway through baking.
08 -
Let cakes cool in pans for 10 minutes. Remove cakes, discard parchment, and transfer to a wire rack to cool completely before frosting.
09 -
In a mixing bowl, beat butter and cream cheese until smooth, approximately 30 seconds. Add half the confectioners’ sugar and salt, mix on medium-low until incorporated. Scrape bowl, add remaining sugar, lemon juice, vanilla, and cream. Continue blending on medium until creamy and even. Fold together with a spatula if necessary.
10 -
Place one cake layer on a serving plate. Pipe a border of buttercream around the edge. Fill the centre with 180–240 millilitres lemon curd. Add another cake layer, repeat border and curd. Top with third cake layer. Frost sides and top with remaining buttercream, smoothing or decorating as desired.