Preheat your oven to 350 degrees Fahrenheit. It's important to ensure the oven is at the right temperature before baking to achieve an even rise. Next, take a 9-inch round cake pan and cut out a piece of parchment paper to fit the bottom. This will help prevent sticking. Generously spray the pan and parchment paper with nonstick cooking spray, ensuring that every part is coated. Set this aside while you prepare the batter.
In a large mixing bowl, combine unsalted butter, granulated sugar, lemon zest, lemon extract, and vanilla extract. Use a handheld mixer or a stand mixer fitted with a paddle attachment to beat the mixture on medium speed until it becomes light and fluffy, which should take about 5 minutes. Don't rush this step; the air whipped into the mixture helps the cake rise!
Once fluffy, add in the large eggs, one at a time, mixing well after each addition. This ensures each egg is fully incorporated before adding the next. Don’t forget to scrape down the sides of the bowl to ensure everything is well mixed. Set this mixture aside.
In a separate bowl, whisk together all-purpose flour, cornstarch, baking powder, baking soda, and salt. This step is crucial as it evenly distributes the leavening agents and creates an even texture in your cake.
Gently fold the dry ingredients into the wet mixture using the mixer on low speed. Be careful not to overmix; you want to see some lumps and dry streaks remaining. Overmixing can lead to a dense cake, and that’s not what we want!
In a small bowl, whisk together the full-fat milk, fresh lemon juice, and canola oil (or melted coconut oil). Using a rubber spatula, gently fold this mixture into your batter until it’s just combined. Again, be cautious not to overmix.
Pour the batter into the prepared cake pan and bake for 28 to 30 minutes. You’ll know it’s done when the top is firm to the touch and slightly golden. A cake tester or toothpick inserted in the center should come out clean or with a few moist crumbs.
Once baked, allow the cake to cool in the pan for about 5 minutes. After cooling, gently run a knife around the edges to loosen it, and then carefully turn it out onto a cooling rack to cool completely. This step is key for a moist cake, so be patient!
While the cake cools, let’s make the frosting. In a large bowl, combine cream cheese and unsalted butter. Using a mixer, beat on medium speed until light and fluffy, which should take about 3 minutes. This step makes the frosting airy and smooth.
Next, reduce the speed to low and gradually add in the confectioners' sugar, lemon zest, fresh lemon juice, lemon extract, and salt. Beat until these ingredients are just combined, then increase the speed back to medium. Mix until creamy, which should take about 2 minutes.
Finally, add in the remaining full-fat milk to the frosting, and continue to beat until it’s very light and fluffy, about 2 to 3 minutes. If it seems too thin, gradually add more confectioners' sugar. If it’s too thick, add more milk, one tablespoon at a time.
Once the cake has completely cooled, place it on a cake stand or large plate. Spread the top and sides evenly with your cream cheese frosting. If desired, you can decorate it with fresh lemon slices for that extra touch!
This frosted cake can be stored in the refrigerator for up to 3 days. Just remember to take it out an hour or two before serving so it can come to room temperature. Enjoy!
