This is a slightly altered version of a recipe I found on the website www.431food.com
2 large or 3 small leeks, cleaned and chopped, white parts only
1 bunch kale, stems removed, chopped fairly finely. About three cups
1 tablespoon of olive oil
Salt and pepper for seasoning
1/3 cup sour cream
1/3 cup ricotta cheese
1/3 cup grated Parmesan cheese
1/4 teaspoon nutmeg
1 17.3 ounce package of frozen puff pastry (two sheets), thawed
Egg wash made with 2 eggs and 2 tablespoons of water
1 tablespoon of poppy seeds (I really dislike the flavor of poppy seeds, so omitted them)
Preheat the oven to the baking temperature specified on the pastry box .
Prepare a baking sheet by covering it with parchment paper.
Heat a sauté pan over medium high heat and add oil.
Sauté leeks and kale until softened but not caramelized, approximately six minutes.
Season the mixture thoroughly with salt and pepper.
Remove from heat and let cool.
In a small mixing bowl, blend the sour cream, ricotta and Parmesan cheeses and the nutmeg.
Once the leek mixture is cool add it to the cheese mixture.
Make the egg wash.
Refer to the dough cutting diagram at right ( a modified version of the excellent diagram at the 431 website). Solid black lines are cuts, red dotted lines are markers.
Place a sheet of parchment paper on your board and dust lightly with flour.
For each dough-sheet, roll the dough out slightly on the parchment sheet to form a rectangle approximately ten inches wide by twelve inches tall.
In the center of the pastry mark out the 7" X 6" rectangle by a slight indentation with a blunt knife (the red dotted line in the diagram). Do not pierce the dough.
At one end of the sheet cut out the 2½" X 2" rectangles at the corners (X in the diagram). Keep these, you'll need one or both later.
Down the long sides cut uniform, slanted strips about 3/4" to 1" wide as shown in the diagram.
Discard the end pieces that do not form a uniform strip.
Place one half of the filling in the center of the dough (section Z in the diagram) keeping it clear of the strips.
Fold the end flaps (Y in the diagram) over the filling toward the center. If there is a gap between them in the center, use the cut our rectangles (X in the diagram) to fill in. Don't go crazy getting them to seal, they will be covered later by the strips.
Brush the top of the "parcel" with egg wash.
Starting from the end where the strips go to the end (left-hand end in the diagram) take a strip and fold over the top.
Take the strips one at a time from alternate sides. (see the photo at right).
After each strip is folded, brush it with egg wash to allow the subsequent strip to stick.
When all the strips have been folded, brush the entire strudel with egg wash.
Sprinkle the poppy seeds over (if you are using them).
Using a long spatula carefully move the strudel to the baking sheet.Discard the parchment paper you have just been working on.
Take a new sheet, dust with flour, and repeat all the steps from the rolling out using the second pastry sheet.
Bake in the preheated oven for 30 to 35 minutes (or whatever is specified on the box) until golden brown.
Rotate pans after 15 minutes and check on browning (don’t over cook).
Allow the strudel to cool.
Slice across the strudel for serving.