Preheat oven to 400° F. Line a baking sheet with parchment paper. Set aside.
Place one sheet of puff pastry, do not unfold, on a lightly floured surface. Roll out with a rolling pin until the sheet is increased into a rectangle – about 13 x 9 inches. Place the pastry on the prepared baking sheet.
Brush pastry, from edge to edge with egg wash. Spread a layer of salsa over top of the egg wash, leaving 1/2-inch of space between the salsa and the edges of pastry.
Split open 4-5 poblano peppers and lay them across the sauced pastry - use however many of the first 4 to 5 peppers you can fit.
Top the peppers with a layer of grated cheese and then dot with salsa.
Open up the last 4-5 poblanos, place over top of the first layer, dot more salsa over each pepper and add same amount of each cheese.
Roll out the second piece of puff pastry and place it over the top of your salsa, cheese and pepper layers.
Press the edges together with your fingers and gently fold 1/2-inch of the edges up to create a rim for the tart. Press with the tines of a fork. Dip the fork in flour if the fork sticks to the puff pastry during pressing.
Brush with egg wash from edge to edge. Use a fork to poke venting holes through the top pastry.
Bake for 20 to 25 minutes or until puffed and golden brown, add a sprinkle of cheese, optional, and bake 5 more minutes.
Cool for 10 minutes before cutting into squares and serving. Serve warm.