Preheat your oven to 375F degrees.
Chop your butter into cubes. In a food processor. Add in the cold butter cubes, flour, sea salt, and sugar. Pulse until the butter is mixed in.
Slowly add in the ice cold water. Start with ⅓ cup and see if it feels soft enough and sticks together. If not, add 1 additional tbsp at a time, but I wouldn't go over ½ cup total.
Remove the dough from the processor, and form it into a ball. Cut it in half and wrap each half in plastic wrap. Store it in the fridge for 30 minutes- 1 hour to harden.
Preheat oven to 400F degrees.
Take your dough balls out of the fridge & roll them out onto a floured surface until they're about 1/8-1/4 in thick. You want them both to be in a shape of a rectangle and about the same size.
Take one rectangle and lay it out onto a parchment lined baking sheet. Top with as much jam as you'd like but leave space on the edges.
Add the other rectangle piece on top. Then using a fork, press all the edges with a fork to make sure to close the pop tart. You can brush egg wash over the top if you'd like but it's optional.
Bake for 15-20 minutes until slightly golden and cooked through. Cool completely.
Meanwhile, make the glaze by mixing all the glaze ingredients together.
Pour the glaze all over the pop tart, except for the edges, and then add sprinkles. Cut into 8 pop tarts and enjoy!