Preheat oven to 325°.
Beat butter and sugar with a mixer until fluffy.
Add vanilla and egg; beat
Add flour and salt; mix.
Transfer dough to a floured surface, form into a disk, roll until 1⁄4" thick
Using a 2" fluted round cutter, cut out cookies and transfer to parchment paper-lined baking sheets, spaced apart.
Chill for about 30 minutes.
Using a 1 1⁄4" plain round cutter, cut out centers of half the cookies; discard centers.
Bake cookies until lightly browned, 10-12 minutes; cool.
Dust cookie rings with confectioners' sugar.
Place 1 tsp. jam in center of each whole cookie; spread to within 1⁄3″ of edge
Top each with a cookie ring.