In a cocktail shaker or quart Mason jar muddle the sugar and mint leaves.
Add the strawberries and lime juice; muddle to completely break down the berries.
Add the citrus rum and a large handful of ice. Shake vigorously.
Strain into a 16-ounce glass with fresh ice. Fill with club soda.
*the key limes I used were very small (about an inch in diameter). I would suggest using the juice of 1-2 limes, tasting the cocktail when mixed and adding more lime juice should your taste feel it’s warranted.+muddling is combining ingredients, usually sugar and herbs, in the bottom of a glass and mashing together with a wooden cylinder used for this purpose.