In a small, heat proof measuring cup, add the dried hibiscus flowers. Pour the hot water over the tea and allow to seep for 10 minutes. The water will turn into a glorious shade of magenta. (Be aware, this tea can easily stain, so quickly wipe up any spills. I find vinegar can lift the stains from counters if used immediately upon any accidents).
Drain the infused hibiscus tea from the measuring cup and discard the used leaves. Add the lime juice to the tea and put in the fridge to cool.
While the hibiscus is seeping, beat the butter until smooth with a stand or hand mixer. With the mixer on low speed, gradually add the powdered sugar until completely combined.
Gently add three tablespoons of the infused hibiscus and lime tea to the buttercream and beat until fully incorporated. The buttercream will become a lovely shade of natural pink.
Ice the cupcakes with your preferred method (I used a piping bag), and decorate with sprinkles. Store finished cupcakes in an airtight container for 3 days at room temperature, or up to seven days in the fridge