Preheat oven to 375 degrees
Line cookie sheets with parchment paper
Cookie Directions: Beat butter, oil, sugar, and powdered sugar with the electric mixer until combined.
Add eggs, vanilla, and peppermint extract to the butter mixture. Beat to blend.
Add to a large bowl flour, baking soda, and cream of tartar.
Whisk to combine.
Slowly begin to add the flour mixture to the butter mixture.
Beat immediately after each addition.
Don't overmix.
Use the mini cookie scoop, drop the dough onto the cookie sheets.
Bake at 375 degrees for 8-12 minutes. (Or until the edges are slightly brown)
Allow to slightly cool before transferring to the wire racks to cool completely.
Icing Directions: Add butter, vanilla, peppermint extract, and 1/4 cup of milk together in a bowl.
Whisk to combine until the mixture is smooth.
Stir in 1 cup of powdered sugar at a time.
Mix after each addition. Continue to mix until smooth. (Total of 4 cups of powdered sugar) Use a large spoon to drizzle the icing on the cookies.