Green, purple, and gold colored sugars for dusting
Grease a bundt pan well with butter and flour or baking spray containing flour.
Combine brown sugar, cinnamon and Kosher salt in a small bowl.
In a large mixing bowl, using a fork, stir together all-purpose flour, 1 1/2 cup whole wheat flour, granulated sugar, baking powder, soda, salt.
In a small bowl, whisk together buttermilk and 2 tablespoons melted butter. Add buttermilk mixture to flour mixture and stir with a large wooden spoon until all flour is incorporated.
Turn onto a well floured (with whole wheat flour) surface, dust with more flour.Using your hands shape and pat dough into a 16 x 5 – inch rectangle. Brush with 1 tablespoon melted butter. Sprinkle with sugar/cinnamon mixture – leaving 1/2-inch border. Fold dough over filling. Cut into three pieces for easy transfer into bundt pan. Transfer to bundt pan and gently press seams back together. Brush top of dough with remaining 1 teaspoon of butter.
Bake in a heated 425-degree oven for about 25 minutes or until edges are barely golden. Let cool in pan for 5 minutes. Flip pan over and turn onto a cooling rack or a serving plate (depending on where you want your icing to pool!)
Whisk together cream cheese, milk and confectioners sugar – adding more sugar or milk depending on consistency desired. Drizzle over warm cake.