Preheat oven to 350 degrees. Line two baking sheets with parchment paper.

In the bowl of a stand mixer, beat the butter and sugar until light and fluffy. Mix in the salt, vanilla and egg.

Gradually add the flour, about 1/2 cup at a time. The dough should be soft, but not sticky.

Transfer the dough to a piping bag (or large zip-top bag) fitted with a large star tip. Pipe the dough into 2 inch circles on the prepared baking sheets, leaving about 2 inches between cookies.

Using a wet finger or thumb, make a small indent in the center of each cookie. Place about 1/4 teaspoon of jam into the center of each cookie.

Bake for 12-14 minutes, or until very lightly brownen on the bottom and edges. The tops of the cookies should still be pale. Transfer to wire racks to cool completely.