Preheat oven to 425 degrees F (220 degrees C). Line a baking sheet with parchment paper.
Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 8 minutes. Drain bacon slices on paper towels; crumble into smaller pieces. Reserve drippings in the skillet.
Cook onions and apples in the same skillet until tender, about 5 minutes. Stir in chicken strips, jalapeno jelly, thyme, and salt.
Unfold puff pastry sheet on a lightly floured surface. Roll into a 9x10-inch rectangle. Transfer to the prepared baking sheet.
Spread chicken mixture over the pastry, leaving 1 inch around the edges. Sprinkle with Cheddar cheese and black pepper. Press edges with a fork, forming a decorative border.
Bake in the preheated oven for 10 minutes. Remove and sprinkle with bacon. Continue baking until pastry is golden brown, 5 to 10 minutes more. Sprinkle with parsley.