1. Dissolve sugar in water in a small pot at low temperature, stirring continuously.
2. Wash the lime or lemon with hot water and dry.
3. Grate the zest and press the juice. Then add both to the sugar syrup. Let the syrup cool.
4. Add the sparkling wine to the syrup. Pour the mixture into a wide metal bowl. Cover and place in the freezer.
5. An ice layer should have formed on the sparkling wine mixture after about half an hour. Rake up the whole mixture thoroughly with a cooking spoon and return to the freezer.
6. Let it freeze for another 2-3 hours, stirring occasionally.
7. Wash the redcurrants and remove from their stems.
8. Cook briefly in a small pot with the honey. Then leave to cool.
9. Mix the redcurrants into the sorbet, blend with your Braun Multiquick hand blender and fill into glasses.
10. Garnish with mint leaves.