To make the sugar syrup, combine caster sugar and water in a saucepan over medium heat. Stir until dissolved and bring to a boil carefully.
Remove from heat once clear and allow to cool completely.
In a glass, add 20ml of the cooled syrup along with lime juice, mint leaves, strawberry pieces, and black pepper.
Add crushed ice and pour in the non-alcoholic alternative.
Top with soda water.
Gently muddle everything to release flavors.
Add extra ice if needed and garnish with a mint sprig.
This Strawberry Mojito Mocktail is best served immediately for maximum freshness.