In large mixing bowl combine salt & butter. Using electric mixer, beat butter until smooth.
Add sugar, egg, & water. Continue mixing until combined.
Gradually add flour 1 cup at a time & continue mixing until incorporated.
Form ball of dough with your hands by kneading dough for roughly 4 minutes. Place dough back in bowl & cover with saran wrap. Place in fridge for 1 hour.
Remove dough from fridge & place on a flat floured surface.
Roll dough into thin (about ½ cm. thick) flat square. Use cookie cutter to cut out circle of dough.
Spray cupcake tray with baking spray.
Press each circle of dough into one cupcake mold (there may be excess dough on the top which is totally fine!).
In medium saucepan, heat blueberries & butter over low heat until juicy (about 10 minutes).
Pour blueberries & juice into mixing bowl & add cranberry sauce. Stir to combine.
Add corn starch, sugar, lemon juice, & salt to mixture. Stir to combine.
Fill each pie cup about ½ full of filling.
Cut remaining dough into strips & cover pie cups by pressing edges of dough strips & excess dough from the cup together. Brush top of pies with whisked egg.
Preheat oven to 350 F. Bake pies for 25-30 minutes of until filling begins to bubble. Remove from oven & let cool completely. Carefully remove from cupcake tray, serve, & enjoy!