In a small saucepan, heat diced strawberries, strawberry jam, and lemon over medium-high, stirring constantly, until just before a boil. Remove from heat.
In a small bowl or cup whisk together soy milk and maple syrup. Set aside.
Lightly flour a work surface and roll out the puff pastry into a square about ⅛" thick. Using a knife, cut out 3-inch x 4.5-inch rectangles.
Place ½ of the rectangles onto the prepared cookie sheet and brush the edges with soy milk mixture.
Spoon roughly 2 tbsp of the diced strawberries into the center of the rectangles.
Place a second rectangle on top of each and use a fork to crimp the edges.
Brush each pop tart with a bit of soy milk mixture and cut a small vent slit.