Preheat oven to 325 degrees. In mixing bowl, cream together butter and powdered sugar. Add vanilla. Blend in flour and salt and mix thoroughly.
Roll tablespoons of dough into 1 inch balls. Place on cookie sheets lined with silicone baking mats or parchment paper. Press down with your thumb or a spoon in the center of each cookie. Fill centers with a teaspoon of preserves.
Bake 15-20 minutes until bottoms are just golden brown. Cool on wire racks. When cool, dust with powdered sugar. Makes 2 dozen.
Notes
*Unless otherwise indicated, all of my recipes use salted butter.