1/4cupcanola OR coconut oil (melt coconut oil first, if using)
For the Creamy Lemon Frosting:
4ouncescream cheese, VERY soft
1/4cupunsalted butter, VERY soft
2cupsconfectioners' sugar, sifted
1teaspoonsfresh lemon zest
2teaspoonsfresh lemon juice
2tablespoonsfull-fat milk, more if needed
For the Lemon Cake:
Preheat oven to 350 degrees (F). Cut out one 9-inch round segment of parchment paper to line your cake pan with. Spray the pan generously - sides and bottom - with nonstick cooking spray, then place the parchment paper cut out in the bottom of the pan and spray again. It's important to make sure every bit of pan and paper are sprayed so your cake doesn't get stuck. Set pan aside.
In a large bowl using a handheld electric mixer (or in the bowl of a stand mixer fitted with the paddle attachment), combine the butter, sugar, lemon zest, lemon extract, and vanilla extract; beat on medium speed until light and fluffy, about 5 minutes (don't skimp on time here!). Add in the eggs, one at a time, beating well after each addition, and scraping down the sides of the bowl as needed. Set aside.
In a separate bowl, whisk together the flour, cornstarch, baking powder, baking soda and salt, mixing well to evenly combine the ingredients. Add the dry mixture into the wet ingredients and mix on low speed until everything is just barely combined. You should still see some lumps and dry streaks. Turn mixer off. In a small bowl combine the milk, lemon juice, and oil, whisking well. Using a rubber spatula, fold the ingredients into the mixture, mixing until everything is incorporated, but being sure not to overmix. Scrape the batter into the prepared pan and bake for 28 to 30 minutes, or until the top is firm and slightly golden, and a cake tester (or toothpick) inserted in the center comes out clean, or with a few moist (but not wet) crumbs clinging to it.
Allow the cake to cool in the pan for 5 minutes before gently running a knife around the edges to loosen any stuck bits, then turning it out onto a cooling rack to cool completely.
While the cake cools, you can make the frosting.
For the Creamy Lemon Frosting:
In a large bowl using a handheld electric mixer (or a stand mixer fitted with the paddle attachment) beat the cream cheese and butter on medium-speed until light and fluffy, about 3 minutes. Reduce the speed to low, then add in the confectioners' sugar, lemon zest, lemon juice, lemon extract, and salt; beat until combined. Increase the speed back to medium and mix until creamy, about 2 minutes. Add the milk and continue beating the frosting until very light and fluffy, about 2-3 minutes. If the frosting seems too thin, add a little more confectioners' sugar, starting with one tablespoon at a time; if the frosting seems to thick, add in a little more milk, starting one tablespoon at a time.
When the cake has completely cooled, place it on a cake stand or large plate; spread the top and sides evenly with the frosting. Decorate with fresh lemon slices, if desired.
The frosted cake will stay fresh, when stored in the refrigerator, for 3 days. Simply take it out of the fridge an hour or two before serving so it can come to room temperature.