• To Prep: Preheat oven to 350º

To Make the Cookies:

• In a medium mixing bowl, whisk together flour, baking powder, and salt. Set aside.
• In the bowl of a stand mixer, cream butter and sugar together until light and fluffy, then beat in the egg and vanilla.
• Slowly add the flour mixture to the bowl of wet ingredients, stirring as you add, until the cookie dough comes together.
• Roll dough out on a floured surface to ¼-⅓ inch thick, sprinkling a little flour on top as needed to keep dough from sticking to your rolling pin.
• Cut out your cookies and arrange them on the prepared cookie sheet so that no cookies are touching.
• Place the cookie sheet in the freezer for 4-6 minutes.
• Bake in center of oven for 10 minutes, until cookies no longer look wet on top, but aren’t yet brown. Remove from oven and let cool completely before frosting.

To Make the Icing:

• While the cookies cool, make the icing by whisking together all icing ingredients until smooth.
• When cookies are cool, scoop a spoonful of icing on top of each cookie, spreading out the icing in a circular motion toward the edge.
• Lay each cookie on a flat surface to allow the icing to set for about 10 minutes. You'll want a crust on top of the icing before you decorate, but the icing doesn't need to be fully hardened.

To Decorate:

• For the round cookies, pipe a couple strands of black icing from one side of the cookie to the other, with a slight "droop" like you'd see on a strand of real Christmas lights.
• For tree-shaped cookies, pipe diagonal lines from one side to the other to mimic strands of Christmas lights wrapping around a tree.
  
• Gently press miniature M&Ms into the icing along the piped lines.