Remove the paper labels and strings from the tea bags. Place the tea bags in a large heatproof bowl or Pyrex pitcher, along with the 10 washed spearmint leaves.
Heat 8 cups of fresh, cold water to boiling.
Steep the tea and chill it:
Pour the boiling water into the bowl over the tea and spearmint. Gently stir everything around with a spoon.
Steep the tea and mint leaves for 10 minutes. (You can go longer if you like your tea to be really strong.)
Then remove and discard the tea bags and leaves. (Compost them if you can!) Cool the tea to room temperature, and then stick it in the fridge to chill for several hours or overnight until it's really, really cold.
Serve the tea:
Drop ice cubes into tall glasses and then pour in the tea. Stir in sweetener if you desire. Garnish the glasses with fresh spearmint leaves and serve them up!
Option if fresh spearmint leaves aren't available:
Instead of fresh spearmint, you can substitiute 1-2 spearmint herbal tea bags. Add them to the black tea bags and steep them as directed above.
Depending on the brand, the spearmint tea may have other herbs or flavorings in the blend, and you can decide if these will work for you in your iced tea. Avoid caffeinated mint teas, since there will be plenty of caffeine from the black tea in this recipe.
Notes
The amount of fresh spearmint leaves used in this recipe gives a subtle mint flavor to the iced tea - it is not overwhelmingly mint at all. If you prefer a stronger mint flavor, just add in extra spearmint leaves when steeping the tea.
You can experiment with your favorite kind of tea, whether other black tea varieties, green, or herbal teas.