Preheat oven to 350° and grease a 9x13 baking dish. I used a glass pyrex.
In a medium saucepan over medium low heat, heat the milk until it starts to simmer. Once simmering, turn off heat and add the tea bags. Let steep as the milk cools. Once milk is cool, remove tea bags.
In the bowl of a stand mixer, beat the butter, sugar and brown sugar together until light and fluffy. Add eggs one at a time, beating between each addition. Add the vegetable oil, sour cream and vanilla. Mix until combined.
In a separate bowl, mix the dry ingredients together. Flour, baking powder, baking soda, cinnamon, cardamom, ginger, salt, nutmeg and pepper.
Alternate adding the flour mixture and cooled tea to the wet ingredients. Starting with adding 1/3 of the flour. Then 1/3 of the tea. Repeat until all added and just combined. Pour into 9x13' and bake for 36-40 minutes, until top is golden browned and springs back when lightly touched. Let cool before frosting.