To make the hibiscus tea concentrate, bring 3 cups water to a boil, add hibiscus tea, stir, remove from heat and let steep for 30 minutes.
Strain into a jar or glass container using a fine mesh strainer and add sweetener to taste. I found 1/3 cup (amount as original recipe is written // adjust if altering batch size) was about the right amount, using half agave nectar, half cane sugar. Stir to dissolve and let cool.
To make two margaritas, add ice, cooled hibiscus tea concentrate, lime juice, tequila and 1 Tbsp agave nectar (optional // amount as original recipe is written // adjust if altering batch size) to a cocktail shaker and shake vigorously to combine.
Pour over two glasses with ice. We love this oversized ice cube mold for cocktails. Salt or sugar rim is optional. Garnish with lime wedge. If too strong, dilute with a splash of sparkling water.
Store hibiscus concentrate covered in the fridge for up to 2 weeks, though best when fresh.
*Nutrition information is a rough estimate calculated with the optional agave nectar. *Hibiscus tea concentrate adapted from Bon Appétit