If using grated pumpkin or butternut squash, place in a colander and salt lightly. Knead in the colander, squeezing out as much water as possible. Let stand for an hour to drain. You can opt to drain even further by transferring the grated pumpkin or butternut squash to a cheesecloth and wringing all the excel liquid out. Set aside until ready to use.

Heat 2 tablespoons of olive oil in a large, deep frying pan or wide pot and add the greens in batches. Season with a little salt and pepper, and stir and cook until wilted and all the liquid is cooked off, about 10 to 15 minutes. Remove from heat, transfer to a colander, and drain thoroughly. Transfer to a large mixing bowl.

In the same frying pan or wide pot, add another 2 tablespoons of olive oil and heat over medium heat. Add the fennel, onions, leeks, and scallions and cook over medium heat until wilted and translucent, about 10 minutes. Transfer to the same mixing bowl as the greens.

Add the grated carrot, pumpkin or butternut squash to the frying pan or wide pot and cook over medium heat to wilt, about 8 minutes. Transfer to the mixing bowl.

Season the filling mixture with salt and pepper.

Preheat the oven to 350F/175C. Lightly oil two baking sheets, or line them with parchment.

Prepare the fillo: On a clean work surface, roll out the fillo in front of you horizontally and cover with a kitchen towel and then a damp towel on top. You have to work fast, especially if the kitchen is hot. Take one sheet of the pastry and brush it with olive oil. Take a second sheet and stack it on top, brushing that with olive oil, too. Cut the fillo into 3 or 4 equal size strips, 3- to 4-inches/ 7 ½ - 10-cm wide, as desired.

Take a heaping teaspoon of the filling and spread it across the bottom of each strip. Fold in the sides and roll up to form cylinders. Place seam side down on an oiled or parchment-lined baking sheet. Continue until all the filling and fillo are used. Brush the surface of each cylinder with a little olive oil.

VARIATION: Shape the pitarakia into triangles. To do so, place one strip on top of the other, oiling both, as above. Place a heaping teaspoon of the filling in the center bottom end of the double strip, about a half inch / 1.25-cm from the edge. Take the right- or left-hand corner, whichever suits you more comfortably, and bring it up to opposite side to form a triangle. Fold over across the width, then repeat from the opposite direction, continuing this way until you reach the top edge, the same way one folds a flag. Place seam-side down on a baking sheet and brush the top with olive oil.

Bake the pitarakia for about 20 minutes, remove, cool slightly, and serve.

You can prepare the cylinders or triangles and freeze them, well-covered, then bake them off directly from the freezer to the oven.