Mushroom & Asparagus in Puff Pastry

Heat a saute pan over medium high heat.
Once heated, add the oil to the pan.
Add the sliced shallots and saute until translucent.
Add the sliced garlic and saute until fragrant.
Turn up the heat to high and add the Asparagus and Dry Thyme. Saute for about 1 minute.
Add the white wine and reduce.
This will cook the asparagus while the wine reduces.
When the wine is mostly reduced leaving only 1-2 tbsp in the pan, add the sliced mushrooms.
Saute the mushrooms until the wine is absorbed into the mushrooms and they have taken on some color.
Season with Kosher salt and black pepper
Refrigerate the filling until it is cool.
This is key to filling puff pastry, the filling needs to be cold. The cold butter in the puff pastry is what will make the pastry rise. If you add hot filling to the pastry it will melt the butter, giving a less than ideal baked result.

Preheat the oven to 375° with the rack in the center of the oven.
Remove the puff pastry from the freezer to allow it to thaw enough to become pliable. Approximately 15 minutes.
If you are using grocery store puff pastry that is folded, you may want to let thaw a bit longer to allow it to be unfolded and pressed flat. Follow the steps below once flatened.
If using a half sheet that is not folded, skip this step and follow the steps below.
Once the puff pastry is semi thawed, cut both sheets in half and then half again. This will leave you with 8 rectangles. 4 for the bottom and 4 to top the filling.
Place 4 of the rectangles of puff pastry onto a sheet pan lined with parchment paper or a baking mat.

Spread 1 tbsp of dijon mustard onto each of the puff pastry sections on the sheet pan. Leave ¾" around the edges to allow for egg wash.
Divide the mushroom and asparagus filling between the 4 rectangles of pastry on top of the dijon.
If there is excess, you can reserve aside to plate warm on top or side of the baked pastry.
Top with the cheese, divide between the 4 filled puff pastry.
Mix the egg with about 1 tablespoon of water and whisk until combined.
Brush the egg wash onto the pastry around the filling.
Top with the remaining puff pastry.
Begin with one corner, press down to seal the two puff pastry sheets together. Work your way around each rectangle pressing to seal all the way around.
Brush the outside top of the puff pastry.
At this point, if the puff pastry is very soft return to the refrigerator or freezer for 15 - 20 minutes to get the butter in the pastry to reharden.
If the pastry is still firm to the touch you can bake immediately.
Bake on the center rack of the oven for 25 minutes. If you want to check the color of the pastry at 20 minutes that is ok. This will help determine if you need more bake time.
The pastry should be risen to about 3/4" to 1" tall and the color should be golden brown. Adjust bake time if needed, this could depend on the oven.
Remove the baked golden brown puff pastry from the oven.
Let rest for 5-10 minutes to cool, the contents will be hot. Or serve immediately if serving as entree.

To Serve as an Appetizer - cut into 2" squares or diamonds. This size is easy to pick up and eat. Drizzle with some Balsamic Reduction to add some tangy sweetness.
To Serve as an a Entree - Prepare the red wine sauce while the pastry is baking. Hold hot so it is ready to serve when the pastry comes out of the oven.
You can leave the pastry whole or cut the pastry in half on the bias to show the filling to be seen. Spoon the sauce onto the plate.
Enjoy!