Preheat the oven to 350°F (175°C). Grease a 9×9-inch light metal baking pan and line it with parchment paper.

Place the Earl Grey tea and lavender in a food processor and pulse until finely ground. Pass the mixture through a sieve to separate any large pieces.

In a medium bowl, whisk together the flour, Earl Grey tea, lavender, baking powder, baking soda, and salt. Set the flour mixture aside.

In a large bowl, combine the softened butter and granulated white sugar. Cream them together using an electric mixer on high speed for about 2 minutes.

Add the eggs and vanilla bean paste to the butter mixture and beat on medium speed until the mixture becomes pale and smooth, about 1 minute.

Gradually add in the buttermilk and the dry ingredients, mixing on low speed. Continue until everything is combined and the batter is smooth. Use a rubber spatula to scrape down the sides of the bowl as necessary.

Pour the batter into the prepared pan and bake for 38-44 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan on a wire rack for 30 minutes, then use the parchment paper to lift it out of the pan. Allow the cake to continue cooling on the rack until completely cooled.

While the cake cools, prepare the Earl Grey milk soak. In a small saucepan, heat the milk over low heat until steaming, then add the Earl Grey tea and lavender. Let the mixture steep for 15 minutes, then remove from the heat.

Pass the mixture through a sieve to remove the tea and lavender, and allow the milk to cool.

Transfer the Earl Grey milk to a liquid measuring cup or another pouring container. Stir in the sweetened condensed milk and vanilla bean paste. Set the soak mixture aside for later use.

Place the lavender in a food processor and pulse until finely ground. Pass it through a sieve to remove any large pieces.

In a large mixing bowl, beat the softened butter on high speed using an electric mixer until pale and fluffy, about 5 minutes.

Add the cold cream cheese to the bowl and mix on high speed until fluffy, about 1 minute.

Sift in the powdered sugar, then add the lavender and vanilla. Mix on low speed until everything is combined, then increase the speed to high and beat for an additional minute until fluffy.

If desired, add purple food coloring and mix until combined.

Once the cake has completely cooled, use a sharp knife to trim off a very thin layer from the top. This will make it easier for the Earl Grey milk to absorb into the cake. Transfer the cake to a serving plate.

Use a wooden stick or the handle of a wooden spoon to poke holes all over the top of the cake. (A honey dipper handle works well for creating smaller holes.)

Slowly pour the Earl Grey milk mixture over the cake, allowing it to absorb into the holes. Be patient, as the liquid will take time to soak in.

Once the milk has absorbed, spread a thick layer of lavender cream cheese frosting over the top of the cake using an offset spatula.

Cut the cake into 16 slices and serve!