For the filling:
In a large sauté pan, melt butter over medium heat. Add onions, season with salt and pepper, and cook, stirring occasionally, until onions start to caramelize (20-25 minutes).
Add mushrooms and continue to sauté until deep golden brown.
Sprinkle flour over onions and mushrooms, stirring to combine. Cook for 1 minute.
Add beef stock and 1 teaspoon thyme, stirring until it simmers and thickens.
Turn off heat, then add about 3/4 of the diced Cooper® cheese and mix well. Set aside to cool.
Assemble your crostata:
Preheat oven to 400°F.
Unroll pie crust on a baking sheet lined with parchment paper.
Heap cooled onion mixture in center of crust. Then fold edges up and over, leaving the center open. Pleat crust every 1-2 inches all the way around.
Place remaining diced Cooper® Sharp over the center.
In a small bowl, beat egg with 1 teaspoon water and brush outside of pastry. Bake 24-26 minutes or until golden.
Garnish with remaining thyme. Let cool and set for 10-15 minutes before serving.
We promise you won’t miss the pie plate.
*Consuming raw or undercooked meats, poultry, seafood, shellfish, or eggs may increase your risk of foodborne illness.