Brush the zucchini slices with some oil and either place the on a grill and cook on both sides or brown them in a cast iron pan; once they are grilled/browned, place them on a platter or baking sheet, cut each strip in half and set aside.
Preheat oven to 375°F
Bring a large pot of water to a boil, prepare an 8-inch square baking pan with a scoop (about 1/2 cup) of tomato sauce along the bottom; set aside
In a medium bowl , mix together the ricotta, egg, 1 tsp salt, 1 tsp pepper and parsley; set aside
Place one sheet of pasta into the boiling water and cook for 1-2 minutes; remove from pot (making sure to drain all the water) and place on a wooden board. Place about 1/4 cup of the ricotta mixture onto the pasta sheet, top with a piece or two of the zucchini and fold up (as directed in the photos above); place the finished pasta pockets in the prepared baking dish and continue with the rest of the pasta sheets.
At this point, if you would like to cook more than 4 pockets, you can prepare another baking pan as directed above (also, a 9 x 13-inch baking pan will hold about 8 pockets); otherwise, place the remaining folded pockets on a baking sheet and place in the freezer. Once they are frozen place them in a large Ziploc bag and place in the freezer for another time (if cooking from frozen add about another 20 minutes)
To make the bechamel, melt the butter in a medium saucepan over medium heat. Whisk in flour and continue whisking until it turns into a paste/roux, about 2 min (do not let it brown). Gradually add milk and continue to whisk and continue cooking until sauce thickens, 4 to 5 more min. Season with salt and pepper.
Pour bechamel over pockets and sprinkle with parmigiano. Bake for about 40 minutes or until warm all the way through.Serve with a large, green salad and some crusty bread!