Add 100g blueberries to a jug along with the lime juice, sweetener and mint leaves. Crush the blueberries slightly to help release more of their juices, and gently press the mint leaves to ‘bruise’ them – this will enhance the minty flavours too.
Pour in the rum and lemonade and stir together.
Add ice to the serving glasses and pour over the mojito mixture. Add the extra lime slices to the glasses along with the rest of the blueberries and a few extra mint leaves. Serve.