Preheat oven to 425F.

Soften the butter by letting it sit at room temperature for 40 minutes or microwave it for about 15-20 seconds. Add the powdered sugar and mix thoroughly.

Next add the egg white, vanilla extract, salt and mix well.

Finally, add the flour and mix well.

Line a large baking sheet with parchment paper.

Place the dough into a disposable pastry bag with a large star tip and pipe cookies onto the baking sheet. The cookies should be about 2 inches in diameter.

Using a 1/4 thick stick, gently press in the center of each cookie, about half way. You want to make a little dent, not a hole. Fill the centers with a little bit of jam.

Bake at 425F for about 8-10 minutes, or until the sides of the cookies are starting to turn golden brown.