Cut Out Sugar Cookies (without Baking Powder or Baking Soda)

Place the butter and sugar in a stand mixer fitted with a paddle attachment. Beat on medium-high speed until light and fluffy, about 3 minutes.
Add egg and mix on low until smooth, about 30 seconds. Beat in vanilla.
Slowly mix in salt and flour, being careful not to over mix. I usually stop when I still have some flour remnants around the bowl.
Shape the dough into a large disk and wrap in plastic wrap. Refrigerate for about 2 hours to make sure the dough is completely chilled.
Preheat oven to 350 F. Line two baking sheets with parchment paper.
Remove dough from the fridge and allow to sit out for about 10-15 minutes. Lightly flour a mat or surface and roll out the dough until its about ¼ inch thick. I like to have thicker cookies. Cut with cookie cutters, and re-roll dough as many times as needed until all the dough has been shaped.
Bake cookies for 10-12 minutes, or until lightly golden brown around the edges. Allow to completely cool before frosting.
To make frosting blend butter milk and vanilla until smooth. Add powdered sugar and mix until completely smooth. You can add more or less powdered sugar to get your desired consistency. Add food coloring once mixed and ready if you want to decorate the cookies with different colors.