Heat the water to about 95°C (203°F) — just below a full boil. Add the dried hibiscus flowers and steep for 8–10 minutes. Strain out the flowers and return the hot tea to a pitcher.
Stir in the honey while the tea is still warm so it dissolves fully. Let the tea cool to lukewarm.
Stir in the lemon juice and 1 Tbsp orange blossom water. Taste, then add up to 1 additional teaspoon only if needed — the floral note should stay subtle.
Add the clapped (not muddled) mint leaves to the cooled tea. Refrigerate and let infuse for 10–15 minutes, then remove and discard the mint to prevent bitterness.
Continue chilling the drink until fully cold, about 1–2 hours.
Fill glasses with plenty of ice. Pour over the chilled hibiscus mint cooler and garnish with lemon slices and fresh mint leaves.
