Preheat oven to 350 degrees. Line a 12 count muffin tin with paper liners and set aside.
In a medium bowl, whisk together cake flour, baking powder and salt.
In the bowl of a stand mixer fitted with a paddle attachment, beat sugar and olive oil on medium high speed until light and fluffy, about 2 minutes.
Add eggs, one at a time until well blended. Add vanilla and lemon zest and mix until well combined. With a spatula, add 1/3 of the flour mixture, half the milk, second third of flour mixture, remaining milk and last third of flour mixture. Do not overmix.
Divide the batter evenly among the prepared muffin cups. Bake for 18 minutes or until a toothpick inserted in the middle of the cupcakes comes out clean. Remove from oven and let cool on wire rack. While cupcakes are cooling make frosting.
In the bowl of a stand mixer combine butter, sugar and culinary lavender. Beat on low speed until blended, about one minute. Add the vanilla and milk and increase speed to medium and continue to beat for 4 minutes until smooth and creamy. Add more milk, if necessary, until you reach a good spreading consistency.
Divide the buttercream into two equal bowls. Add some of the violet gel to the buttercream in one bowl and some of the cornflower blue gel to the buttercream in the other bowl. Mix until well blended, adding more gel to reach desired color.
To a large piping bag, fitted with the 2D tip (following the video referenced above) add the violet buttercream to one side of the bag and the cornflower blue buttercream to the other side of the bag.
Pipe the top of cooled cupcakes as outlined in video. Sprinkle tops of cupcakes with Wilton Sugar Pearls, if desired.