Process together flours, sugar, and butter until crumbled. Then add egg and process again until doughy.
Wrap that dough in plastic wrap in a disc shape and refrigerate at least 30 min.
Lay out parchment paper, sprinkle with tapioca flour, place dough down, another piece of parchment paper on top and roll out into a rectangle.
Use a pizza cutter to remove edges so it's straight and cut into 10 rectangles.
Move that parchment paper to a baking sheet, then place in the fridge.
Meanwhile take two piping bags or 2 ziplock bags, cut off the ends, and fill one with jam and one with peanut butter.
Line the center of half your pop tart squares.
Place other halves of dough on top, and press edges down with a fork. Poke a few holes in the top.
Bake at 350 for 20 min and then cool completely.
Mix icing ingredients together, spread on top of pop-tarts and enjoy!
Keep stored in the fridge.
