Preheat oven to 400°F. Line a cookie sheet with parchment paper or use non-stick cooking spray.
Mix the tapioca starch with the fruit spread and set aside. Mix egg with water and set aside.
Take one thawed puff pastry and roll it evenly out to a 10x16 rectangle. (Keep other puff pastry chilled until ready to roll out). Cut the pastry sheet into 8 equal rectangles and place them on cookie sheets.
Use a small pastry brush to brush the bottom 1/2 inch edge of the puff pastry rectangles with egg/water mixture. Place a spoonful onto each rectangle until all the spread is used.
Place cookie sheets into the refrigerator and take out the second puff pastry. Roll out again to 10x16 rectangle and cut into 8 rectangles. Cut slits (if desired) then place them on top of the fruit spread filled rectangles. Crimp edges with a fork and then egg wash the top.
Bake for 16-20 minutes until golden brown and puffy.
While they bake, make the icing by mixing melted butter, vanilla extract, almond extract, and powdered sugar with a teaspoon of milk at a time until desired consistency.
Once cooled, use a piping bag or Ziplock bag to frost the strudels and serve.