Preheat the oven to 350 degrees Fahrenheit. This is an essential step because a well-preheated oven ensures that your cupcakes rise and bake evenly. While the oven heats up, grab your muffin tin and spray it lightly with cooking spray before lining it with cupcake liners. This will prevent the cupcakes from sticking, allowing them to easily pop out once baked.
In a medium bowl, whisk together the cake flour, granulated sugar, baking powder, baking soda, lavender buds, and salt. This combination of dry ingredients is crucial to achieving the perfect texture. Make sure there are no clumps, and everything is well mixed.
Next, add the buttermilk, milk, clear vanilla, lavender extract, and vegetable oil to the dry ingredients. Using a stand mixer with a paddle attachment or a hand mixer, beat the mixture just until combined. Overmixing can lead to dense cupcakes, so mix until you don't see any dry flour.
In a separate bowl, whip the egg whites until they reach medium-stiff peaks. This step adds air to the cupcakes, making them light and fluffy. Be careful not to overbeat; you want the texture to be just right.
Gently fold the whipped egg whites into the batter. Use a spatula to incorporate them without deflating the mixture. You should see a light and airy batter that’s ready to be baked.
Scoop the batter into the prepared cupcake liners, filling each about 2/3 of the way full. This will allow room for the cupcakes to rise without spilling over. Once filled, place the muffin tin in the preheated oven.
Bake the cupcakes for 20 to 25 minutes. To check for doneness, insert a toothpick into the center of a cupcake; if it comes out clean, they are ready. The tops of the cupcakes should bounce back when lightly pressed, indicating they are perfectly baked.
While the cupcakes cool, prepare the frosting. In a mixing bowl, add the unsalted butter and beat with the paddle attachment for 1 to 2 minutes until smooth and creamy. This step is crucial for a fluffy frosting.
Add the lemon juice, lemon zest, salt, and powdered sugar to the butter and mix on low speed until the sugar is mostly absorbed. Scrape down the sides of the bowl to ensure even mixing.
Now, add the milk one tablespoon at a time, mixing on medium-low speed. As you add the milk, scrape down the sides of the bowl regularly. Beat on medium-high for 2 minutes until the frosting is white and fluffy. If desired, you can tint the frosting a light purple to match the lavender theme.
Once the cupcakes are completely cooled, pipe the frosting on top in a lovely swirl. Finish by garnishing with a sprinkle of lemon zest and a few more lavender buds for an elegant touch.
