Whisk flour, cinnamon, nutmeg, baking powder, salt, baking soda, sugar and brown sugar in a medium bowl. In a separate bowl, whisk the egg, melted butter, and buttermilk. Add the wet ingredients to the dry ingredients slowly until the dough is well combined.
Heat vegetable oil in a large, heavy bottomed pot to 350 degrees F. Fold the dough onto a floured surface and press it into a circle 1 inch thick with your hands. Use round cookie cutters or a large can and a small spice jar to punch out the doughnuts. Carefully place the doughnuts into the hot oil and fry in batches until golden brown, about 2 minutes per side. Remove doughnuts and place them on a paper towel lined plate to cool.
Whisk together 1/4 cup milk, powdered sugar and maple syrup in a bowl. Dip the cooled donuts in the glaze. Sprinkle with chopped walnuts.
Pour 6 cups milk of your choice, cinnamon, nutmeg and honey in a saucepan. Bring to a gentle simmer over medium heat, whisking constantly. Serve in your favorite mug.