This is a GREAT party dish…easy and fun to make and can be made ahead. Be sure to make a bunch, these are favorites that go quickly!
12 ounces fresh mushrooms (eg., button, crimini, wild mix), very finely chopped
TO MAKE FILLING:
Melt butter with oil in large sauté pan over medium heat. Add shallots and garlic to pan and sauté 2-3 minutes until translucent. Add mushrooms and sauté over medium-high heat for 6-7 minutes or until slightly browned.
Add sherry and reduce mixture until the liquid has evaporated. Salt and Pepper to taste, add thyme and let mixture cool.
TO ASSEMBLE WELLINGTONS:
In a bowl, thoroughly mix egg yolk with water to make an egg wash.
On the middle of each pastry square, place 1 teaspoon of the cooled mushroom mixture and one cube of filet.
Brush edges of pastry with egg wash, fold pastry square in half and completely seal edges, crimping with a fork.
Place Wellingtons on a baking sheet lined with parchment paper that has been lightly sprayed with nonstick cooking spray. Just before baking, brush tops of Wellingtons with egg wash.