Add the egg, vanilla extract, and sourdough discard and mix until combined.

Whisk together the dry ingredients in a separate bowl and fold them into the butter mixture.

Knead the dough until you have a smooth, soft dough and wrap it in plastic wrap.

Place the dough in the refrigerator and let it rest for at least one hour.

Take your dough out of the refrigerator and roll it out on a well floured work surface until you have a 1/4-inch thick disk.

Use your favorite cookie cutter to cut out your cookies, and use a smaller cookie cutter to cut out a small hole in half of your cookies.

Place your cookies on a lined baking tray and bake them in the center of your preheated oven for 10-12 minutes or until golden.

Transfer them to a cooling rack to cool completely before adding the jam filling.

Once your cookies have completely cooled, add one teaspoon of jam to the center of half your cookies.

Place the cookies with a hole on top of the jam and dust them with powdered sugar before serving.