Preheat oven to 350°F. Grease an 8-inch cake pan and line the bottom with parchment paper.
In a medium bowl, whisk together flour, baking powder, baking soda, tea, and salt. Set aside.
In a large bowl, beat eggs, sugar, and vanilla with a whisk until thickened and smooth.
Mix in oil, followed by buttermilk until blended.
Using a rubber spatula, fold dry ingredients into wet ingredients until just barely combined.
Pour into prepared cake pan and drop from 2 inches onto counter to get rid of air bubbles.
Bake for 25-30 minutes, or until a toothpick entered into the center of the cake comes out clean.
Cool in pan for about 15 minutes, then transfer to a wire rack to cool completely.
Prepare Honey-Lemon Glaze:
Whisk together honey, lemon zest, and 2 tbsp lemon juice in a bowl.
Gradually whisk in powdered sugar until smooth.
Add lemon juice as necessary to achieve a very thick, but pourable consistency.
Spread glaze over cooled cake.
Buttermilk: I prefer using full-fat buttermilk in most cakes because it adds flavor and richness, and keeps the cake moist for longer. But you can definitely substitute whole milk for buttermilk in this cake. If you do, omit the baking soda. Lavender Earl Grey Tea: I use Twinings Lavender Earl Grey Tea for this recipe, but you can use any Earl Grey tea you prefer, and for the lavender flavor add 1/2 teaspoon of lavender extract (or 1 tsp of crushed culinary lavender buds).