Preheat the oven to 350°F.
Mix together the butter and sugar until they are just combined. Add the vanilla.
In a medium bowl, mix together the flour and salt. Add the dry mixture to the butter-and-sugar mixture. Mix on low speed until the dough starts to come together. Dump onto a surface dusted with flour and shape into a ball. Wrap in plastic and chill for 30 mins.
Roll the dough ¼-inch thick.
Cut dough into roughly 3 squares. Place 1 tsp of Bonne Maman Plum Preserves in the center of every square. Cut 1″ slit in every corner pointing towards the center.
Pull down alternate corners of the square to meet in the center.
Place on a baking tray covered with parchment paper. Bake until golden, about 12–13 mins. Cool on a wire rack and dust with powdered sugar.
Yields: 30 cookies