Preheat oven to 350 degrees. Slice round pie crust to create four large rectangles (eight rectangles total). In four of the rectangles, cut out a small heart, about the size of a strawberry, with a butter knife.
On the remaining rectangles, layer an even amount of nutella and strawberry jam, leaving a small perimeter around the edge for sealing.
Top with cut out rectangle and pinch ends together. Press sides with a fork to seal. Carve up a slice of a strawberry in the shape of a heart and place it in the opening of the pastry.
In a small bowl, whisk together egg and 1 tablespoon of water. Brush egg mixture over pastries and sprinkle with granulated sugar.
Arrange pop-tarts on a lined baking sheet. Bake for 13-15 minutes, or until golden brown.
Recipe by Rachel Schultz at https://rachelschultz.com/2013/01/27/strawberry-nutella-homemade-pop-tarts/