- Heat oven to 350 degrees. Line cupcake tins with 18 paper liners.
- Mash the berries with ½ cup sugar in a medium bowl. In another bowl, cream the butter with remaining cup of sugar. Whisk in the eggs, salt and vanilla. Alternately add the berries and flour. Stir until just combined.
- Spoon into cupcake liners. Bake for 16 to 18 minutes, until center spring to the touch. Allow to cool.
- In a mixer, combine the butter, lime juice and lime zest. Alternately whip in the powdered sugar and milk until smooth and creamy. If desired, add green food coloring. Ice cooled cupcakes.
- Decorate the tops of each margarita cupcake with a strawberry and lime slices, and evenly distribute lime zest and salt.