• Preheat the oven to 325°F. Line 2 baking sheets with parchment paper and set it aside.

Sugar Coating

• In a medium bowl combine the cinnamon and sugar coating. Set aside.

Cookies

• Using a handheld mixer, combine the butter, shortening, sugar, eggs, and vanilla in a large bowl.
• To the butter mixture, add the flour, cornstarch, salt, baking powder, and cinnamon. Mix until the ingredients are incorporated.
• Using a ¼ cup (or 2 scoops of dough with a 2 tablespoon scoop), set the dough onto a lined cookie sheet, about 2 inches apart. (I usually put 6 cookie dough balls onto each cookie sheet.) Use your hands to shape and slightly flatten each ball of dough. (If you used 2, 2 tablespoon scoops, combine the scoops of dough into one large cookie.)
• Roll each cookie in the cinnamon and sugar mixture and place back on the sheet.
• Bake for 12 minutes for a softer cookie, up to 14 minutes for a firmer cookie.
• Remove cookies from the oven and let them cool completely before frosting with the buttercream.

Churro Buttercream

• In the bowl of a stand mixer with a paddle attachment, combine the butter, sugars, and cinnamon.
• Start mixing on low speed until the sugar is incorporated with the butter. Increase the mixing speed to high and beat until smooth and fluffy, about 2 minutes.
• Adjust the consistency with milk as needed.
• Store unused buttercream in the refrigerator in an airtight container and bring it back to room temperature before using it to pipe or frost.
• Use buttercream to frost completely cooled cookies.
• Store frosted cookies in the refrigerator. Serve cookies cold.