Put the strawberries in a medium bowl, sprinkle 4 tablespoons of the sugar over them, and toss gently. Set aside, covered, for at least 1 hour, or refrigerate for up to 3 hours.
In a small bowl, mix together the fromage blanc, 1 tablespoon of the remaining sugar, lemon zest, lemon juice, and vanilla extract. Taste and add the additional sugar if necessary to correct the balance of flavors. Spoon the fromage blanc into the center of a shallow serving bowl.
Spoon the strawberries and their juices around the fromage blanc, garnish with mint leaves and serve immediately.
