Whisk the balsamic vinegar, agave nectar, cardamom, a pinch of salt and a few generous grinds of pepper in a medium bowl.
Tumble in the strawberries and blackberries, sprinkle the mint over them and gently toss, being careful not to bruise the berries. Taste and adjust the seasonings to your palate.
Photograph by Kat Teutsch
Recipe courtesy Aarti Sequeira for Food Network Magazine