Cake is Bravetart's vanilla butter cake, scaled down for two pans rather than three and with the zest of two lemons added to the batter.
Filling is homemade lemon curd: zest and juice of two lemons, six egg yolks, and 200g sugar heated until thickened, then 1 stick cold butter stirred in off heat.
Frosting is Bravetart's Swiss meringue buttercream with 1tsp lemon extract and juice of 1 lemon added.
Garnished with candied lemon peel, scaled down to 1 lemon.