Pour the tea and lemonade into a large pitcher, then add the vanilla extract.
In a mixer or food processor, puree a handful of fresh blackberries. If you don’t have a food processor, you can muddle the blackberries with a wooden spoon.
Add 2 tablespoons of the pureed blackberries into the pitcher. If you muddled your blackberries, you’ll have seeds in your drink. You’ll want to strain those out before serving. To do this, after mixing your pitcher, add a strainer to the top of another pitcher and pour from the first pitcher into the new one. Repeat until you have strained most of the blackberry seeds.
Stir and refrigerate until ready to serve.
Before serving, add ice, lemon slices and a few whole blackberries. Enjoy!
If you have a large pitcher, you can add 1/2-1 cup of water or more ice to fill it to the top.