Steep the tea bags in 1 cup hot water for at least 3 minutes, or until steeped to your liking. Squeeze the bag into the water before discarding it. Fill 2 12-oz glasses with ice to the top. Pour half of the tea over each. Top each glass with 1/4 cup sliced strawberries (optional), 1/4 cup heavy cream, 1 tablespoon powdered Besti, and 1/8 teaspoon vanilla extract. Stir well. Add more sweetener to taste if needed.