Preheat the oven to 350 degrees F (180 degrees C) and lightly spray 12 large muffin cups with nonstick cooking spray. Set aside.
Sift together the flour, baking soda, baking powder, salt, nutmeg, and cardamom.
In a medium bowl, combine the milk and buttermilk. Set aside.
In a large mixing bowl, using a handheld or stand mixer on medium speed, cream the butter for 2-3 minutes until smooth.
Turn the speed to low and gradually add the sugar. Continue to mix until the mixture lightens in color.
Add the eggs one at a time, beating just until combined.
Add the dry ingredients in thirds, alternating with the milk mixture, mixing just until smooth. Do not over mix
With a large ice cream scoop, scoop the batter into the prepared muffin cups, filling them approximately ⅔ full.
Bake for 20-25 minutes, until the tops are firm to the touch and lightly golden.
While the muffins bake, set up two bowls to dunk them in.
In one bowl add the melted butter, in the other bowl whisk together the granulated sugar and cinnamon.
Let the donuts cool enough to handle them.
Dunk them in the melted butter, then coat with the cinnamon sugar.