Crisp phyllo sheets encase a wonderful and tasty mushroom filling with cheese. It's an excellent appetizer for parties as it can be made ahead and is a crowd-pleaser!
In a large skillet, melt4 tablespoons unsalted butter and 2 tablespoons olive oil over medium heat. Add ¾ cup chopped green onion and 2 garlic cloves, and cook to soften for 1 minute.
Add 1 ½ pounds mushrooms, sliced, and cook over high heat until they begin to lose water. When the liquid has almost evaporated, add ¼ cup dry sherry or white wine and cook for 30 seconds.
Remove from heat and mix in 1 cup grated parmesan cheese, ½ cup grated Fontina cheese and 2 tablespoons chopped fresh parsley. Season with salt and black pepper to taste and freshly grated nutmeg, if using.
Let the filling mixture cool down completely and then stir in 3 eggs and ½ cup sour cream before assembly.
When ready to assemble:
Preheat the oven to 350ºF (180°C). Line a baking sheet with parchment paper.
On a clean surface, have 1 cup clarified butter ready and a pastry brush.
Cut 8 phyllo sheets into 4 pieces (I use scissors).
Arrange one sheet on a flat surface and brush, carefully, with clarified butter. This is easier if you dot the entire dough with small amounts of butter and then spread. If you tear it, don't worry, patch it up as best as you can. Repeat with the remaining three sheets of phyllo dough, stacking them one on top of the other.
Sprinkle 2 tablespoons dry breadcrumbs along one short side, leaving 3 or 4 inches from the border.
Put the cooled mushroom mixture on top of the breadcrumbs, then sprinkle 3 tablespoons pecans or walnuts on top.
Starting on the short side near you, fold the dough over the filling. Brush the dough with butter.
Fold the two sides inwards. Fold the packet as many times as necessary, brushing the dough with butter every time. When you're done folding and you have a tight packet brush the entire surface with butter making sure the dough is sealed.
Bake for 30 minutes, until golden brown and crisp.
Cool to room temperature, cut into slices and serve.
Notes
The filling is enough for 2 strudels; work with one at a time so the phyllo dough doesn't dry out.You can freeze the strudels for a month, well wrapped. Thaw at room temperature, unwrapped, and reheat in a warm oven until crisp.