Preheat oven to 350°F. Line standard size muffin tin with paper liners. Set aside.
In a small bowl, whisk together ½ cup tea infused milk, egg whites, and vanilla. Set aside.
In the bowl of a stand mixer fitted with paddle attachment (or using a hand mixer), cream together ½ cup (113g ) tea infused butter and ¾ cup sugar until smooth. Add liquid milk-egg mixture. Mix on medium speed until combined. Mixture may look curdled at first. Continue to mix until combined. Scrape down bowl as needed to ensure thorough mixing.
In a large bowl, whisk together cake flour, baking powder, and salt. Add to mixing bowl in two additions, mixing on low speed. Scrape down bowl as needed.
Evenly distribute cupcake batter among prepared muffin tin, filling each paper liner about ⅔ full. Bake for 20-25 minutes until toothpick inserted in center of cupcake comes out clean. Rotate muffin tin midway through baking for even cooking. Allow cupcakes to cool in tin for 10 minutes before unmolding. Allowing cupcakes to completely cool on wire rack. Cupcakes may be frosted once cooled to room temperature.