Heat the vinegar water with sugar in a small pot over medium heat. Bring to a boil, then add salt and stir until the sugar and the salt are dissolved. Reduce the heat to low.
Put the shallots, mint and parsley in food processor and pulse to finely chop, then transfer the mixture to a small storage container. Pour the hot brine over the shallot mixture. Cover the container with a lid and refrigerate until ready to serve or let stand at room temperature until ready to serve.