Preheat oven to 350 degrees F. Line a baking sheet with parchment paper. 

Cream butter and sugar together in a stand mixer or in a bowl with hand mixer. Add in vanilla. Beat more. Add in salt and flour. Dough will become crumbly but stick together them hand kneaded. 

Using your hand take out 1 tablespoon full of the dough. Knead in the palm of your hand and then roll into a ball. Slowly press your thumb into the center and place on baking sheet 2 inches apart. Fill the hole with lingonberry jam. 

Bake for 12 to 14 minutes. Transfer to wire rack to cool. Store in airtight container.