Begin by bringing 1 cup of filtered water to a gentle simmer in a small saucepan over medium heat. Add a handful of fresh sage leaves and let them steep for 5 minutes.

Introduce a generous amount of blackberries to the saucepan. Return the mixture to a simmer, allowing it to heat for another 5 minutes while mashing the blackberries.

Remove from heat and strain the mixture into a heatproof container, discarding the sage leaves and pulp. Stir in maple syrup or honey while warm, followed by cold water and lemon juice.

Transfer the iced tea to the refrigerator and let it chill for at least 30 minutes.

When ready, fill a tall glass with ice cubes and pour the iced tea over the ice.

Garnish with whole blackberries and sage leaves, and add a lemon slice if desired.