Beat butter and cream cheese with electric mixer on medium speed until thoroughly combined. Scrape bowl down as needed during this process.
Combine salt with flour in a separate bowl.
Slowly add the flour/salt mixture to the cream cheese mixture, beating on low until combined. Again, stop occasionally to scrape down the bowl.
Form dough into a ball, then divide ball in half.
Flatten each half with your hands and wrap each in plastic wrap
Refrigerate for several hours.
Remove from refrigerator and preheat oven to 375
Line cookie sheet with parchment paper. (I found it would be easier to use the rimless sheets so you have room to maneuver when crimping the edges.)
Roll each disc of dough to approx. 1/8 inch thick.
Decide on size for your pastries. I used the tops of a peanut butter jar for the round pastries and the top of a Jif Whipped Peanut Butter tub for the rectangle. Alternatively, you can measure approx.. 4 inch wide strips and cut to the length you wish. You will need one rectangle/circle/square for each top and one for each bottom.
Place cutout bottom on cookie sheet. Brush with egg mixture.
Place approx.. 1 T. filling topping in the center of dough and spread out toward edges, making sure to leave approx. ½ inch room at the edges without topping. Sometimes I use a bit more filling if the dough seems to hold it.
Top with another dough shape and crimp edges with fork.
Brush tops with more egg mixture. You can also sprinkle with sugar if you like.
Bake for approx. 20 minutes or until light golden brown
Remove to cool in pan on wire rack.