In your food processor, add flour, sugar and salt and pulse a couple of times until just combined.
Next add your butter and pulse until crumbs just develop. Slowly add the water in until a rough ball of dough forms. Remove the dough and cover with plastic wrap and place in the refrigerator for 30-45 minutes to rest.
Remove dough from fridge and add a bit of flour to a clean counter and place dough on it. Using a rolling pin, quickly roll dough out to about 1/4 inch thickness.
Cut out rectangle sizes for pop tarts. You should be able to get at least 5 pop tarts from this dough which means you will need 10 rectangles.
For the Pop Tart Assembly:
Preheat oven to 350 degrees.
Add about 1 1/2 to 2 tablespoons of seedless jam or preserves to the center of 5-6 rectangles leaving about 1/4 inch of space around the outsides.
Place plain rectangle on top and press the edges together. Using a fork, crimp the edges to seal them. Place back in the fridge for about 15-20 minutes to firm up before baking.
Bake for about 20-25 minutes or until golden brown and puffed. Cool until room temperature or just warm.
For the Icing:
Whisk together confectioner's sugar, jam or preserves, milk and vanilla until nice and smooth. Spoon over cooled pop tarts and serve.