Crushed peppermints or Andes peppermint crunch baking chips, optional
Preheat the oven to 350 degrees F (or 325 degrees F for convection bake) and line several half sheet pans with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment (or in a bowl using a handheld electric mixer), add the butter, oil, granulated sugar and powdered sugar. Sprinkle the cinnamon, baking soda, baking powder, salt, allspice, ginger, and nutmeg across the top of the sugars. Mix until well-combined and super creamy, 1-2 minutes, scraping down the sides of the bowl as needed.
Add the egg, sour cream, molasses, and vanilla and mix until well-combined, 1-2 minutes, again scraping down the sides of the bowl as needed.
Add the flour (see note below) and mix until no dry streaks remain and the mixture is evenly combined; don't overmix.
Scoop the dough into 2-tablespoon size balls (I use a #40 cookie scoop; you can make them smaller or larger) and roll into balls.
Place the cookies several inches apart on the prepared baking sheets. Lightly spray the bottom of a flat-bottomed glass with cooking spray and dip into granulated sugar. Press each cookie to about 1/4-inch thick. (Repeat dipping the bottom of the glass into sugar as needed.)
Bake the cookies for 7-8 minutes until just set. DO NOT OVER BAKE. Err on the side of under baking just slightly.
Let the cookies cool for a few minutes on the baking sheets before removing to a cooling rack to cool completely.
For the frosting, in a medium bowl (can use a handheld or stand mixer) combine the butter, sour cream and vanilla. Mix until thick and smooth and creamy, 1-2 minutes. Add the powdered sugar and cream, and mix until well-combined and fluffy, 1-2 minutes. Scrape down the sides of the bowl as needed. Add additional cream, if needed, to adjust the consistency of the frosting so it is thick but still soft and spreadable.
Frost the cooled cookies and decorate with crushed peppermints, if desired.
Eggnog Frosting: for an eggnog vibe to the frosting (which pairs really well with the gingerbread cookies), sub in rum extract for vanilla extract and use eggnog to thin the icing instead of milk or creamFlour Amount: if you live at high elevation, are in a super dry climate, or tend to pack more flour into a measuring cup, you might consider dropping the flour down to 2 3/4 cups (also, if you aren't weighing the ingredients on a scale, measure with a light hand).Doubling: this recipe can easily be doubled (or tripled).