Wash berries; hull and slice the strawberries. Stem the blueberries. Put all of the berries in a bowl and add the 3 tablespoons of granulated sugar. Let stand for about 20 minutes for the juices to come out.
Scoop half of the sorbet into four to six dessert dishes, brandy snifters, martini glasses, or other dish or glass.
Spoon half of the strawberry-blueberry mixture over the sorbet, and then top with a few tablespoons of yogurt, whipped topping or whipped cream.
Repeat with the remaining sorbet, berries, and topping. Garnish with some mint if you'd like.