Set your oven to 350°F (175°C) and line two cookie sheets with silicone baking mats.
In a stand mixer, cream together the butter, oil, granulated sugar, and powdered sugar. Beat in the egg and heavy whipping cream. In a separate bowl, whisk together the flour, cornstarch, salt, and baking powder. Gradually incorporate the dry ingredients into the wet mixture until a dough forms.
Then, if desired, use a food scale to weigh out 2.2 oz portions of dough for uniformity. Roll the dough into balls and place them on the cookie sheets, pressing into thick disks. Ensure there are 6 cookies per tray.
Next, Place the cookies in the oven and bake for 10 minutes. Allow them to cool completely before frosting.
Beat the butter, powdered sugar, heavy whipping cream, and vanilla extract in a stand mixer until creamy. Divide the frosting between two bowls, coloring one with red gel food coloring and the other with green.
Using the cookie scoop, place a dollop of frosting on each cookie. Turn the cookies upside down on the silicone mat and gently press to form a flat disc of frosting. Repeat with remaining cookies and frosting colors.
Set Frosting: Place the frosted cookies in the freezer for 10 minutes to harden the frosting.
Finish: Gently peel the cookies off the silicone mat. Sprinkle with Christmas-themed sprinkles for a festive touch.