Instructions

1. In the bowl of the a stand mixer fit with a paddle attachment, or in a large bowl with a hand mixer, cream together the butter and cream cheese on medium/high speed until light and fluffy. This should take about 2 minutes.
2. Mix in the vanilla and the salt until well combined.
3. With the mixer running on low speed, add the flour slowly until all incorporated. You will have a very thick and sticky dough.
4. Transfer the dough between two pieces of plastic wrap or parchment paper and press it out to about 1/2" thick. Chill in the refrigerator for about 45 minutes, until easy to handle. You can chill the dough for longer, but may need to let it sit out for a bit before rolling it.
5. Dust a clean work surface liberally with powdered sugar. Take about 1/4th of the dough and dust the top with more powdered sugar. Roll out to a square about 1/4" thick. Keep the rest of the dough in the refrigerator as you work.
6. Using a pizza cutter or bench knife, cut the dough into 2 inch by 2 inch squares.
7. Spread about 1 tsp of filling down the middle of each square, corner to corner. To seal, dab a bit of water on one of the corners without filling and seal it in the center with the other corner. Press to seal so the cookies do not pop open in the oven. Transfer the filled cookies onto parchment lined baking sheets. The cookies will not spread so you can place them fairly close together.
8. Bake at 350 F (170 C) for 14-18 minutes, until just barely golden brown. Transfer to cooling racks to cool completely.
9. Dust cooled cookies with powdered sugar before serving. If you will not be serving right away, wait to dust until right before serving.
10. Store cookies covered at room temperature for about 3 days. They will start to get soggy if not eaten within a few days. I also do not recommend storing them airtight. Place a lid loosely over top or cover with foil or plastic wrap.