Freeze crostini 1 month ahead.
Preheat oven to 450°. Stir together cornmeal mix and sugar in a large bowl; make a well in center of mixture. Whisk together eggs, sour cream, buttermilk, and melted butter in a medium bowl. Add to cornmeal mixture, stirring just until dry ingredients are moistened. Fold in chives and parsley. Spoon batter into 3 lightly greased 12-cup muffin pans (about 1 Tbsp. per cup), spreading batter to cover bottoms of cups. Bake 8 minutes or until set. Immediately remove from pans to wire racks. Serve warm.