In a large bowl, beat butter and sugar with an electric mixer on medium speed until light and fluffy 2-3 minutes. Mix in milk and vanilla. Stir in flour and salt and mix on low speed until incorporated. Gently fold in the sprinkles.

Place a sheet of wax or parchment paper on your work surface and place the cookie dough on top. Place another sheet of wax or parchment paper on top of the dough and roll out until about ¼ inch thick. Remove the top sheet and top with more sprinkles. Gently press into dough with your hand.

Chill in the refrigerator for about 15 minutes or in freezer for about 5 minutes. This will firm the dough up enough so you can get clean cuts with the hearts.

Place chilled dough on work surface and using a small heart shaped cookie cutter, cut out hearts. Gather the dough scraps and press together and roll out again. Top with more sprinkles and cut out more hearts. (I place a small cookie sheet under the dough/wax paper.)

Enjoy immediately or store in an airtight container, in the refrigerator for up to 3 days.