Add the cassava flour and salt to a food processor. Chop the cold butter up into 1/4" thick chunks and add them to the food processor.
Pulse the mixture until the butter is finely chopped and the mixture is crumbly. Add 1/4 cup ice cold water and pulse a few times. Add the remainder of the water 1 tablespoon at a time until the mixture starts to form a crumbly ball.
Transfer the dough onto a lightly floured piece of parchment paper. Form the dough into a ball and split the dough in half.
Working with one half of the dough, gently press the dough into a thick rectangle. Use a lightly floured rolling pin to roll the dough into a rectangle that is 8"x10". Use your hands to straighten out the edges and make them smooth.
Cut the rectangle into 6 pieces. Transfer each smaller rectangle onto a parchment paper lined baking sheet. Repeat the process with the other half of the dough but don't transfer the small rectangles to the baking sheet yet.
Separate one small rectangle from the cut dough onto a cutting board. Spoon some jam onto the rectangle, leaving at least 1/4" of space around the edges. The jam can be about 1/8" thick.
Take one of the rectangles from the baking sheet and place it over the jam filled rectangle on the cutting board. Place your hand over the top of the pop-tart and use a fork to press down all the edges of the pop-tart. Use the fork to poke 3 sets of holes on the top of the pop-tart.
Transfer the finished pop-tart back to the baking sheet and repeat the assembling process with the remaining 5 pairs of dough rectangles. Place the baking sheet with the pop-tarts on it in the freezer.
Let the pop-tarts chill in the freezer for 20 minutes. After 20 minutes, keep the pop-tarts in the freezer and preheat your oven to 350°F.
Once the oven is preheated, bake the pop-tarts for 30-35 minutes. The edges will be just starting to get lightly browned.
Allow the pop-tarts to cool on the baking sheet for at least 30 minutes before transferring to a cooling rack. Let them cool completely before icing them.
For the icing, combine all of the ingredients in a small mixing bowl. Add the coconut milk slowly until the mixture is thick but spreadable. Apply the icing to the pop-tarts and add some organic sprinkles!
Enjoy! Note: I don't recommend toasting pop-tarts that have icing on them.