Move oven rack to the middle position. Preheat the oven to 350°F.
Line the bottom of (3) 9-inch cake pans with parchment paper and lightly spray with cooking spray.
MAKE LEMON CAKE BATTER:
In a large mixing bowl, add flour, baking powder, salt, and baking soda.
Add sugar and vegetable oil in the bowl of a stand mixer fitted with a paddle attachment and beat on high speed for 2 minutes or until pale in color.
Add eggs and mix for 30 seconds.
Add buttermilk, sour cream, vanilla, and lemon zest and mix until combined.
Next, add the flour mixture and mix until just incorporated.
Add hot lemon juice and mix.
While the mixer is still running, slowly add food coloring drops until desired color is reached (optional).
Evenly distribute the batter into the 3 prepared cake pans.
BAKE AND COOL CAKES:
Place the cake pans into the preheated oven on the middle rack and bake for 23 minutes or until a toothpick inserted into the middle of the cakes comes out clean or with a few moist crumbs.
Once baked, remove the cakes from the oven and place on wire cooling racks for 15 minutes. Then, remove the cakes from the pans and cool them completely on wire racks.
While the cakes are cooling, make the frosting.
MAKE LEMON FROSTING:
In the bowl of a stand mixer fitted with a paddle attachment, add powdered sugar, butter, cream cheese, lemon extract, lemon zest, and salt.
Beat on medium-high speed for 3-4 minutes until smooth and creamy.
If you wish to have yellow frosting, add food coloring drops until the desired color is reached.
ASSEMBLE CAKE:
Once the cakes are completely cool, place the first cake on a plate or cake stand and add about ½ cup of frosting. Use an icing spatula to smooth the frosting out.
Place the 2nd cake on top and repeat the frosting process ending with the 3rd cake on top.
Once all cakes are layered, frost the top and sides of the cake, using an icing spatula to get a smooth finish.
Spoon the remaining frosting into a piping bag fitted with a star tip.
Pipe a border along the top and bottom of the cake.
SERVE:
Cut into 12 slices and serve.
Notes
Once the flour mixture has been added to the batter, only mix until just combined. Overmixing can cause the gluten to overdevelop, resulting in a crumbly cake.