For the cupcakes:
Preheat oven to 350 degrees F.
Line 2 cupcake pans with 18 baking cups
Sift together the flour, baking powder and salt in a large bowl.
Place the unsalted butter in the bowl of a stand mixer.
Add the sugar; beat on medium speed until well incorporated.
Add the eggs one at a time, mixing slowly after each addition.
Combine the vanilla extract and milk in a large liquid measuring cup.
Reduce the speed to low and add one-third of the flour mixture to the butter mixture, then gradually add one-third of the milk mixture, beating until well incorporated.
Add another one-third of the flour mixture, followed by one-third of the milk mixture. Stop to scrape down the bowl as needed.
Add the remaining flour mixture, followed by the remaining milk mixture, and beat just until combined.
Mix in the cooled lavender earl grey tea (and lavender sugar) until fully incorporated.
Scoop batter into baking cups and bake for 18 minutes or until a toothpick inserted into the center of a cupcake comes out clean.
For the frosting:
Place the unsalted butter in the bowl of a stand mixer.
Add the confectioner's sugar; beat on medium speed until well incorporated.
Add the vanilla extract, milk, salt, tea, and purple food color, and beat on high speed until light and airy.
Transfer to a piping bag with a large round piping tip and frost each cupcake with Georgetown Cupcake's "signature swirl"(I used a different favorite decorating tip)