Steak, Mushroom and Oyster Pie

I set out to make a steak and mushroom pie with a puff pastry top but when I saw big plump oysters at the grocer's for only 39 cents each, I just had to add them!

Makes 4 healthy servings

5 ounces pearl onions (20 to 25)
2 slices bacon, chopped
2 Tbl butter, divided
2 pounds boneless beef ribeye, cut into one inch cubes
Instant flour (Wondra) for dusting the beef and more for thickening later
1 minced garlic clove
8 ounces beef stock
8 ounces brown ale
1 bay leaf
8 ounces brown or white button mushrooms, halved if large
1 dozen freshly shucked oysters
Salt and pepper for seasoning
1 sheet puff pastry from a 17.3 ounce package
1 beaten egg

Prep the pearl onions by cutting off the root end of each and then placing them in a pan of boiling water for about 30 seconds.  Drain and when cool enough to handle, slip off the skins and set aside.
In a 4 to 5 quart Dutch oven, cook the bacon in 1 Tbl of the butter until relatively crisp.  Remove the bacon with a slotted spoon to paper toweling, leaving the rendered bacon fat in the Dutch oven.
Season the beef cubes with salt and pepper and then dust them with some instant flour.  Brown the cubes, in batches, in the bacon fat until well browned.  remove each batch to a bowl.
Add the second Tbl of butter to the pot along with the minced garlic and saute for about 30 seconds.
Pour the beef stock and ale into the pot, add the bay leaf and simmer for about 5 minutes while scraping up the browned bits up from the bottom of the pot.
Return the beef, along with any accumulated juices, and the bacon to the pot.  Bring up to the boil and then down to a simmer.  Simmer, covered for about 30 minutes, stirring occasionally.
After 30 minutes, add the mushrooms and pearl onions.  Stir and simmer 5 more minutes. taste and adjust for seasoning with salt and pepper.
Using a large slotted spoon, lift the meat, mushrooms and onions out of the pot and transfer to a 2.5 - 3 quart baking dish.  Fish out the bay leaf.  Reheat the gravy and thicken with more instant flour.
Pour the gravy over the meat mixture, let cool for a few minutes, and then scatter the oysters over the top. Push the oysters down into the casserole and then to be safe, sprinkle in a little more instant flour.
Prep the puff pastry by rolling it long enough to cover the baking dish.  You can either just cover the dish with the pastry and crimp around the edges or cut into strips and create a lattice patter as I did.  If you just cover, be sure to vent the pastry.
Brush the pastry with a little beaten egg and then bake in a pre heated 400F oven for 40 to 50 minutes until the top is golden and the stew is bubbly.  Let rest about 10 minutes before serving.