Preheat oven to 400°F. Halve jalapeño peppers and remove seeds and pith.
In a medium bowl, combine cream cheese, Monterey jack cheese, Parmesan cheese, scallions, and salt.
Fill jalapeños with cheese mixture and smooth off the top. Set aside.
Lay out puff pastry and brush with beaten egg then sprinkle with poppy seeds. Cut pastry into ¼ inch strips, then wrap strips of pastry around jalapeños in a crisscross pattern.
Place assembled peppers on a parchment lined baking sheet and bake for 20–30 minutes or until puff pastry is golden in color. Serve with barbecue sauce.
