Preheat oven to 350F. Grease three 5-inch cake pans and line bottoms with parchment paper. Set aside.
In a bowl of a standing mixer with a whisk attachment, beat egg whites on medium speed until foamy. Add 2 tablespoons sugar and continue beating until stiff peaks form. Scrape the meringue in another bowl. Set aside.
In the same mixing bowl, beat egg yolks and 1/4 cup sugar on high speed until thick and light in color, about 5 minutes. Add vanilla, lemon juice and zest. Mix for another minute.
Sift flour and the remaining sugar over top of egg yolk mixture, followed by folding in half of the meringue.
Fold the rest of the meringue into the batter until just incorporated. Pour the batter into the prepared pans evenly and smooth the top.
Bake for 10 to 12 minutes or until the cakes are golden brown and a toothpick inserted in the center comes out clean.
Remove the cakes from the oven and let cool in pan for 5 minutes. Run a thin knife around the cake edge and place the cake on a wire rack to cool completely.
To prepare buttercream, beat butter for a few minutes in a standing mixer with the paddle attachment on medium speed. Add powdered sugar and turn your mixer on low, beat until the sugar incorporates with the butter. Add vanilla and heavy cream, beat on medium speed for another 3 minutes, or until buttercream becomes light and fluffy.
To assemble the cake, place one cake layer on your serving plate and spread with 1/3 cup frosting. Place another cake layer on top, and gently press down a little bit. Spread with another 1/3 cup frosting. Place the last layer of cake on top, smear frosting on the top and sides of the cake.
Cover and refrigerate the cake when you prepare the ganache.
To prepare ganache, place the chocolate and heavy cream in a medium heatproof bowl over a pot of simmering water. Stir the mixture using a wooden spoon until melted and smooth. Let cool slightly. Tint the ganache with a drop of colouring paste.
Remove cakes from the refrigerator. Pour ganache over the top of the cakes. Use an offset spatula to gently push the ganache over the sides of the cake to create the dripping effect.
Let ganache set for 5 to 10 minutes. Insert lollipops on top of the cake.