Heat oven to 350℉/177℃.
Spray an 8-inch round cake pan with baking spray. Set aside
In a small saucepan, heat milk and tea bags until bubbles form around the edges of the milk.
Remove from heat.
Steep for 15 minutes.
Drain tea bags.
Set milk aside.
In a medium bowl, whisk together flour, sugar, baking powder, and salt.
Add egg, egg yolk, milk, oil, and vanilla.
Whisk until smooth.
Pour into prepared pan.
Wrap pan with a baking strip.
Place on a sheet pan.
Bake for 35 minutes, or until cake tests done.
Allow to cool in pan for 10 minutes before turning out.