to prepare your filling, in a saucepan over medium heat, place your berries, honey and lemon juice and begin to stir.
bring the berries to a bubble, and once bubbling, turn down heat to a simmer and simmer for 30 mins or so, mixing every once in a while.
once the jam is ready, remove from heat and allow to cool before using in the pop tarts (place in fridge). the jam is another aspect of the recipe that i highly recommend prepping the day prior, for the simple ease of putting together these pop tarts!
once your dough and jam are both prepared, you can begin putting your pop tarts together! take the frozen dough out of the freezer, and roughly divide it into five balls, which will be used for the five pop tarts we'll make. place all but one dough ball back in the freezer so they remain cold and firm until you're ready to use them.
take a piece of parchment paper atop a flat surface (counter or cutting board will do), and place the dough on top of the paper, before adding a second piece of parchment paper to cover the dough. you'll be rolling out the dough between the two layers in order to facilitate the rolling, as the dough is very sticky!
separate the ball of dough into two of the roughly the same size. roll out one half of the dough so it's roughly 7 cm x 10 cm - it may be a bit larger or smaller give or take. you can make a rough rectangular shape at first, and cut around with a knife to take off any excess dough, adding the extra dough back and rolling it out again as needed.
place the rectangle on a parchment paper-lined baking tray, and repeat the process with the remaining half of the dough.
add 1 + 1/2 or so tbsp of jam to the middle of the dough that is directly on the parchment paper.
now, with your top half of dough, gently place it atop the jam, pressing down the corners delicately with your fingers. using a fork, wet the prongs slightly (otherwise the fork may stick to the dough and remove it), and sink the prongs into the edges around the pop tart. using a skewer or toothpick, you can also poke six holes on the top of the pop tart. (see photos on my site).
finally, the last step, is the egg wash. mix the egg white you set aside earlier with a tbsp water, and using a brush, egg wash the top and edges of the pop tart.
now repeat this process with the remaining balls of dough.
once all the pop tarts are prepared and egg washed on the baking sheet, bake in a preheated oven at 340 for 20 minutes. you can serve these immediately or allow to cool completely and store in between layers of parchment paper in the fridge or freezer. if serving immediately, leave in the oven for 5 mins longer or so (keep an eye) to allow it to get a bit more crispy. if you're storing in the freezer or fridge to re-heat later, i definitely recommend baking in the oven for the best experience --bake it in the oven at 330 or lower for 10 minutes at least when re-heating. i will say you can also eat these cold too!!