Spiced Eggnog Oatmeal Cream Pies

These are chewy cookies with oats and flavored with eggnog cinnamon and nutmeg. Sandwich them together with richly sweet and spiced eggnog buttercream. See my cookie shaping tips above before starting.
Ingredients
1 and 12 cups 190g allpurpose flour spooned leveled
1 teaspoon ground cinnamon
12 teaspoon ground nutmeg I recommend freshly ground
23 cup 53g oldfashioned whole rolled oats
34 teaspoon baking soda
12 teaspoon salt
12 cup 8 Tbsp 113g unsalted butter softened to room temperature
1 cup 200g packed light or dark brown sugar I recommend dark here
2 Tablespoons 30ml eggnog at room temperature
1 large egg at room temperature
1 teaspoon pure vanilla extract
Eggnog Buttercream Filling
10 Tablespoons 142g unsalted butter softened to room temperature
2 cups 240g confectioners sugar
3 Tablespoons 45ml eggnog at room temperature
14 teaspoon pure vanilla extract
pinch each salt ground cinnamon and ground nutme
Instructions
Make the cookies Whisk the flour cinnamon nutmeg oats baking soda and salt together in a medium bowl. Set aside.
In a large bowl using a hand mixer or a stand mixer fitted with a paddle attachment beat the butter and brown sugar together on mediumhigh speed until creamed about 2 minutes. Add the egg eggnog and vanilla extract and beat on high speed until combined about 1 minute. Scrape down the sides and up the bottom of the bowl and beat again as needed to combine.