Preheat oven to 350°F. For the Cinnamon Rolls, mix flour and baking powder in large bowl. Add milk, 1/4 cup of the melted butter, sour cream, butter flavor and vanilla; mix to form a dough. Roll out dough on lightly floured work surface to a 15x11-inch rectangle. Mix brown sugar and cinnamon in small bowl. Brush dough with remaining 6 tablespoons melted butter. Sprinkle with brown sugar mixture. Roll up rectangle from the long end into a log.Cut log into 12 rolls. Place cut-side down in 9-inch round baking pan. Bake 25 minutes or until golden brown. Meanwhile, for the Glaze, mix all ingredients in medium bowl until smooth. Drizzle over warm cinnamon rolls.