Stir All-Purpose Flour (3/4 cup), Dark Brown Sugar (1/2 cup), Butter (6 tablespoon), Chopped Pecans (1/3 cup), Ground Cinnamon (1 teaspoon) and Ground Nutmeg (1/2 teaspoon) together thoroughly in a mixing bowl until it is a uniform mixture. Set it in the refrigerator while you work on the donuts.
Preheat the oven to 350 degrees F (176 degrees C) and spray two donut pans, each with 6 molds, really well with Non-Stick Baking Spray (to taste).
Whisk the All-Purpose Flour (1 1/3 cup), Baking Powder (2 teaspoon), Ground Cinnamon (1 teaspoon), and Salt (1 pinch) together in a bowl to aerate the dry ingredients.
Set up a stand mixer with the paddle attachment and combine the Dark Brown Sugar (3/4 cup) and Butter (2 tablespoon) in its bowl. Beat them together until fluffy.
Add in the Buttermilk (1/2 cup) and Egg (1). Finally, slowly add in the dry ingredients until you have a soft, sticky batter.
Transfer the batter to a piping bag and pipe a thick, single layer into each of the molds. You should get an even dozen.
Take out the topping mixture and crumble it up. Sprinkle a thick layer on top of each donut and press the crumbs firmly into the donut batter so that it all holds together.
Bake them on the same rack of the oven for 15 minutes, until golden brown on top and fluffy.
Let them cool a few minutes, then transfer them to a rack to cool completely. Serve immediately with coffee! They also keep really well for a couple of days sealed in a container.