• Preheat oven to 350 degrees and line one 12-cup muffin pan with paper liners.
• In a medium bowl, whisk flour, baking powder, nutmeg, and salt until well combined. Remove a little of this flour mixture (maybe 3 tbsp) and toss it with the red and green sprinkles in a separate, smaller bowl. Set aside until ready to use.
• In the bowl of your stand mixer (or a large bowl with a hand mixer) beat oil with sugar until well incorporated, about 60-90 seconds. Beat in eggs, one at a time, until fully incorporated, then beat in vanilla.
• On the slowest speed of your mixer, alternatively beat in dry ingredients and eggnog to the oil mixture, starting and ending with the dry ingredients. (Example: stir in 1/3 flour mixture, then 1/2 eggnog, and repeat until all is mixed in). Gently fold in flour-coated sprinkles.
• Fill cupcake liners 2/3 way full with cupcake batter and bake at 350 for 20-22 minutes or until a toothpick inserted into the center of a cupcake comes out clean. Let cool in pan for a few minutes before carefully removing to a wire rack to cool completely.

While they are cooling, make the frosting:

• Stir together the flour and milk in a medium saucepan. Heat over medium heat until it begins to bubble and sputter. Whisk constantly until the mixture thickens to the consistency of thick cake batter (this can happen anywhere between 3-7 minutes, so watch carefully!)
• Remove from heat, stir in vanilla, and let cool completely. While this is cooling, beat granulated sugar and butter for a full three minutes until pale and fluffy. Once the flour/milk mixture has cooled, beat this into the butter/sugar mixture for a full minute or two until fully incorporated.
• Pipe/frost cupcakes, dust with cinnamon, and serve