In a food processer add your sugar and mint leaves. Blend until mint is finely chopped.
In a large bowl add your sugar mixture, oil, eggs, sour cream, buttermilk, rum, lime zest. Mix until combined. Then add your flour, baking powder, and salt. Mix until combined.
Fill your cupcake liners almost to the top (leaving about ⅛ inch of room at the top).
Bake cupcakes at 350 degrees for 22-24 minutes.
Let cupcakes cool.
Raspberry Puree
In a medium saucepan add all of your ingredients. Crush your berries as much as possible. Simmer on medium low heat for about 10 minutes or until the mixture thickens slightly.
Strain your mixture, leaving of all the seeds and mint leaves behind.
Let it cool.
Buttercream
In a stand mixer add your room temperature butter. Mix on high until the butter is soft and whipped. Add your powdered sugar, lime juice, and rum. Mix on low until combined.
Add your cooled raspberry puree. Mix until combined.
If the frosting is too soft you may need to chill it for a few minutes.
Frost your cupcakes and enjoy!
Make sure to store in the fridge in an air tight container.