Preheat oven to 350°F and line baking sheets with parchment paper.
In large bowl, beat butter and sugar using electric mixer until light and creamy, about 3 minutes. Add egg and vanilla; mix until combined.
Add flour and salt; mix on low speed until incorporated.
Refrigerate dough for 30 minutes to an hour.
Flour your surface and roll out the dough to desired thickness (1/8 inch or less).
Use cookie cutter of your choice and place cut outs on lined baking sheets.
Bake cookies just until edges begin to turn golden brown, 11-13 minutes for large cookies, 7-8 minutes for medium cookies, and 5-7 minutes for small cookies.
Let cookies cool on the sheet pan about 5 minutes, then transfer to a wire rack to cool completely before decorating.