In a mixer, cream butter and sugar and then add eggs and vanilla. Add sour cream.
In a separate bowl, combine salt, baking soda and flour. Add to butter mixture, creaming until combined. NOTE: If dough seems too sticky to roll out, place in refrigerator for 20 minutes or so and then continue with the next step.
Roll out on a floured surface to about 1/4 to 1/3 inches thickness. {Yes, seriously. If you make it any thinner, they will be crispy and not as good! This is the trick to making them super soft!}
Cut with cookie cutters and using a spatula, transfer cookies to baking sheet that has either been sprayed with cooking spray or has parchment paper on it.
Bake at 375 degrees F for 7-8 minutes {Yes, seriously. This is another important step! Do NOT overbake!} They won't look done, but just trust me on this, take them out of the oven.
Wait about 5 minutes and carefully transfer cookies to a cooling rack. (This recipe makes several dozen cookies but is easy to half as well.)
In a mixing bowl, cream butter until smooth. Beat in powdered sugar and vanilla until crumbly.
Gradually add milk until frosting reaches desired consistency. Add food coloring and stir until combined. Spread on cooled cookies and ENJOY!! They are SO good!