Preheat oven to 350° F
In a large food processor, combine all ingredients, minus the water to start.
Once flour and butter is combined, slowly drizzle in ice water until it becomes a dough ball.
Flour your surface, then remove dough from processor. If dough is too sticky, add a little bit of tapioca flour.
Place dough in a large baggie, and refrigerate for 1 hour.
Remove dough from fridge, and roll dough out in between 2 pieces of parchment paper until dough is about 1/4" thick.
Using a cookie cutter, carefully cut out shapes. If you have extra dough scraps, you can put it together, knead a bit, then use again for more.
Place dough pieces on a sheet tray lined with parchment paper or a silpat liner.
Add jam, about 1 tbsp to each tart. Be sure to leave plenty of room around the outside so jam doesn't spill out. Place another piece of cut out dough over top.
Gently crimp around the edges.
Brush each pastry with an egg wash or half and half (optional)
Bake for 10-15 minutes, or until golden brown.