Combine first 5 ingredients in a small saucepan over medium heat. Cover and cook 15 minutes. Remove from heat; stir in tea leaves, and steep 2 minutes. Strain mixture through a sieve into a large bowl; discard solids. Stir in buttermilk; cool to room temperature. Add butter, vanilla, and eggs; stir well with a whisk.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, sugar, baking soda, baking powder, and salt. Add flour mixture to milk mixture; stir until combined. Stir in oats. Cover and let stand 15 minutes. Pour about 1/4 cup batter per pancake onto a hot nonstick griddle or nonstick skillet. Cook 2 minutes or until tops are covered with bubbles and edges look cooked. Carefully turn pancakes over; cook 2 minutes or until bottoms are lightly browned.