Pre-heat oven to 350 degrees Fahrenheit.
First saute the mushrooms and onions. In a skillet over medium heat, melt butter and olive oil together and then add mushrooms and pearl onions, stirring so everything is coated with the butter.
Next, add the herbs (leaving whole is fine), red wine and season with salt and pepper and cook until onions are just about tender, 10-15 minutes. Once done, set aside.
In a large pot or Dutch Oven,drizzle with olive oil and add chopped bacon. Cook until fat has rendered, then remove bacon to a plate and set aside. Next, dredge the cubed beef lightly in flour, shaking off any excess and add the beef cubes to the same pot, searing on all sides. You may have to do this in several batches to not overcrowd the pot.
Once all the beef is seared (it will be under-cooked in the middle), remove to a plate and set aside.
In the same pot, add the sliced carrot, leeks and shallot and saute for about 2-3 minutes until the leeks and shallot begin to soften. You may have to add a bit more oil if it's too dry.
Then stir in 1 Tb tomato paste, chopped garlic and chopped herbs and saute for another minute.
De-glaze by pouring in 1 cup of beef stock and using a wooden spoon to scrape all the bits off the bottom of the pot.
Add back the bacon and cubed beef to the pot. Pour in 3 cups of red wine and 2-3 cups of beef stock until just barely covering everything. Add in 2 bay leaves and gently stir everything together.
Cover the
dutch oven with a tight fitting lid and bake for 2-21/2 hours, or until the meat is tender.
While stew is cooking, you can prep the puff pastry.
On a floured surface, roll out the puff pastry to it's a bit thinner, about ⅛th of an inch but not too thin to tear.
Use your pot pie dishes as a guide to cut circles, leaving about 1 inch overhang.
Once stew is done, remove from the oven and add the mushrooms and onions and gently stir everything together. Allow to cool slightly.
Then ladle the stew into preferred Baking Dishes and cover with puff pastry. Cut a small hole into the crust and brush with egg wash. Place pot pies on a baking sheet and bake for about 20-25 minutes or until the crust is golden brown.
Once done, remove from oven and allow to cool for 5-10 minutes before serving.