Melt the butter in a medium saucepan set over medium heat. Add the apples, brown sugar, cinnamon, nutmeg, cloves, and salt.
Cook, stirring occasionally, until the apples are soft and the liquid has reduced slightly, 5-7 minutes. Remove from heat and set aside to cool. Once slightly cooled, puree in a food processor.
Optional step: use a fine mesh strainer to remove some of the liquid from the filling. This can make it easier to spread the filling on the dough.
Preheat the oven to 350 degrees F. Line two baking sheets with parchment paper.
On a clean, lightly floured surface, roll the dough to ¼ thick. Cut the dough into approximately 3x5 rectangles. For 10 pop tarts, you’ll need 20 rectangles (it’s ok if you wind up with less; it just means a smaller yield). Divide the rectangles between the prepared baking sheets.
Brush the edges of the rectangles lightly with egg wash. Divide the filling between half the rectangles (approximately 1 tablespoon per pop tart), leaving space around the edges.
Top with the remaining rectangles and use a fork to crimp around the edges. Brush the remaining egg wash on top. Use fork prongs to poke vent holes in the top of the dough.
Divide the pop tarts between the two baking sheets so they don’t overcrowd the pan. Bake for 25 minutes or until the tops are golden brown. Remove from the oven and cool completely before frosting.
In a small bowl, stir together the confectioners’ sugar, cream, cinnamon and vanilla until smooth. Spread the frosting onto the tops of the pop tarts.