Preheat oven to 375 degrees. Spray a baking sheet with nonstick spray.
Cream together butter and sugars with a mixer until light and fluffy.
Mix in vanilla, salt, and egg.
In a small bowl, whisk together flour and baking soda.
Add flour to butter mixture and blend until a dough forms.
Lightly flour a flat surface, then roll out dough to a little less than 1/2-inch thick.
Use a heart-shaped cookie cutter to cut out 28 hearts (gather and re-roll dough scraps to get enough cookies).
Transfer cookies to baking sheet.
Bake until cookies are golden on bottom, about 8 to 10 minutes. Do not over bake.
Transfer cookies to a wire rack to cool.