Lemon cake: Preheat your oven to 350°F and prepare two 8-inch cake pans. Butter each pan, line with parchment paper, then butter the parchment. Parchment paper helps the cakes release from the pan once they are baked. Now is a good time to prep the lemon zest and lemon juice.

Sift together the all-purpose flour (2 cups/250g), baking powder (2 teaspoons), and kosher salt (½ teaspoon). Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, cream butter (¾ cup/170g), sugar (1 ¼ cups/250g) and the zest from 2 lemons (hold aside 1 teaspoon zest for the frosting) on medium-high (speed 6 on a KitchenAid mixer) until light and fluffy, approximately 3 -4 minutes. Scrape up and down the sides of the bowl once during that time. Then scrape the bowl again and with the mixer on low (speed 2 on KitchenAid) drizzle in the oil (2 tablespoons/30mL), increase the speed to medium-high and mix for another 1-2 minutes. Scrape up and down the bowl and add the eggs (3 large) one at a time, mixing until incorporated. Add vanilla (1 teaspoon) with the final egg and beat on medium (speed 4) 1-2 minutes. Scrape up and down the sides of the bowl.

Add the lemon juice (2 tablespoons) to the buttermilk (⅔ cup/160mL) and stir to mix.

With the mixer on low, slowly add the flour mixture and the buttermilk mixture in alternating additions (⅓ flour, ½ milk, ⅓ flour, stop and scrape the bowl, ½ milk, ⅓ flour) until just a little flour is still showing. Finish mixing until just combined with a spatula, being careful to not over mix your batter.

Divide your batter equally between the two 8-inch cake pans. (I weigh the batter, it's about 500g per cake pan). Bake for 22-30 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs.

Allow the cakes to cool in the pans for 15 minutes, then remove to a wire rack to cool completely. The cakes must be completely cool before assembling and frosting.

While the cakes cool, prepare the white chocolate ganache.

White chocolate ganache: add the white chocolate chips or chopped white chocolate (shy ¾ cup/114g) to a glass or metal bowl and set aside. I've only tested this recipe with Ghirardelli white chocolate chips or a quality white chocolate baking bar.

Heat the heavy cream (2 ounces/60mL) in a small saucepan over low heat until it’s bubbling at the edges and is hot, but do not bring it to a boil. Pour the hot cream over the white chocolate and let it sit about two minutes before stirring it into a smooth ganache.*** Set aside and allow the ganache to cool until it is a thick and spreadable consistency, like peanut butter.

Lemon white chocolate frosting: Melt the white chocolate (4 ounces/114g) using the double boiler method or in the microwave (if you are comfortable using the microwave for melting chocolate). Set aside to cool to room temperature.

Beat the butter (1 cup/226g) in a stand mixer with the paddle attachment (or using a hand-held mixer) on high for 5 minutes. Stop about half way through to scrape up and down the bowl. Add the confectioners’ sugar (2 cups/240g) and mix on low until the sugar is incorporated. Add the heavy cream (3 tablespoons/45mL) and beat on high for another five minutes. Scrape up and down the bowl, add the cooled melted white chocolate, lemon zest (1 teaspoon), vanilla (½ teaspoon) and a pinch of salt and beat 2 minutes more.

Assemble and decorate: Make sure the cakes are completely cool before assembling and decorating. If needed, use a large serrated knife and slice a thin layer off the tops of the cakes to create a flat surface. (save the cut part for snacking or crumbling over ice cream) Place one cake layer onto a cake plate, cake stand or cake board topside up. I like to place about two tablespoons of frosting onto the board to help hold the cake onto the decorating surface. Create a frosting dam around the outside of the cake (this will hold the ganache in place) and then fill with the thick, cooled white chocolate ganache. Smooth with an offset spatula. Place the second layer, topside down, on top of the filling. Frost the rest of the cake with a thin layer of the white chocolate frosting to create a semi-naked look. If desired, use the remaining frosting to pipe rosettes and buttons on the top of the cake. (I used a Wilton 1M for the rosettes, a Wilton 4B for the large buttons and a Wilton 32 for the yellow buttons). If you would like more instruction on how to decorate a semi-naked cake, see my brown sugar cake recipe. If you want a more fully frosted cake, double the frosting recipe.