Whisk together the flour and salt in a medium bowl and set aside.

In a stand mixer, cream the room-temperature butter on medium speed until smooth and light in color, about 40 to 60 seconds.

Add sifted confectioners' sugar and mix until well combined and fluffy.

Gradually mix in the flour and salt mixture until a smooth dough forms, being careful not to overmix.

Roll the dough out between two sheets of parchment paper to about 1/4-inch thick. Refrigerate for at least 30 minutes.

Preheat your oven to 350°F (175°C).

After chilling, cut the dough into bite-sized squares and place them on a lined baking sheet.

Bake for 10 to 12 minutes or until the edges are lightly golden. Allow to cool completely on a wire rack.

Mix softened butter with powdered sugar and vanilla extract in a large bowl. Add milk as needed to achieve desired consistency.

Divide the frosting into three portions, tinting two with red and green food coloring gels.

Once cooled, frost the cookies with buttercream and decorate with festive sprinkles.

Allow the frosting to set before serving.