Heat the oven to 350F. Prepare your cake pans. Brush the bottoms and sides of your cake pans with melted butter. Line the bottoms and sides with parchment paper.
In a medium saucepan, bring the milk to simmer until bubbles just start to form around the outside. Remove the saucepan from the heat.
Place the 6 tea bags into the hot milk and push them down with a spatula to submerge them.
Let the tea bags steep in the milk for 30 minutes.
Remove the tea bags, wrapping each around the end of a wooden spoon to get as much milk out as possible.
Measure out 12 oz/355ml of the tea milk into a measuring cup. If you don't have exactly 12oz, use regular milk to top it off.
To the tea milk mixture, add the eggs, oil and vanilla and whisk to combine.
In the bowl of a stand mixer fitted with a paddle attachment, combine the cake flour, sugar, baking powder, salt, tea and orange zest. On low speed, mix for 1 minute.
With the mixer still running, add in the softened butter pieces, a few pieces at a time. Mix until the mixture resembles cornmeal. You should be able to gather a bit in your hand, squeeze and you have a solid piece. This means the butter is evenly distributed.
With the mixer still on low, slowly pour some of the milk/egg mixture into the bowl JUST to moisten the ingredients, about 4 oz or 1/2 cup of liquid.
Turn the mixer speed to medium (4 or 6) and whip for *two full* minutes. The mixture should be whipped up, thick, and lighter in color. Scrape the sides and bottom of the bowl to ensure everything is properly mixed.
With the mixer speed on low, add the remaining wet ingredients in three parts, scraping down the bowl after each addition.
Once all the wet ingredients have been added, give the bowl a final scrape and mix with a spatula. Evenly divide the batter among the prepared pans.
Bake the layers for 35-45 minutes. Check the cake at 30-35 minutes to test for doneness. If a toothpick comes out clean, and the top of the cake feels springy and set when touched, take the cakes out.
Tap the cake once, firmly against the counter to remove excess steam. If your cakes dome at all, use a clean kitchen towel to gently push the domes down. Cool the cakes for 15 minutes in the pans.
Run a palette or butter knife around the cakes in their pans before turning them out to cool completely on cooling racks.
Wrap the cakes in plastic wrap and chill in the refrigerator a couple hours to firm up.