Melt butter in a large saucepot and heat until just beginning to foam. Add the bay leaves.
Toss the celery and onions into the butter and cook until soft and translucent; add the mushrooms (except for those that are reserved) and cook until the mushrooms are soft.
Add the vermouth.
Remove the bay leaves.
Add the cubed baguette and using a wooden spoon, break up the bread and mix into the vegetables until the bread is soft and begins to fall apart.
Reduce the heat to low and add the oyster liquor to the bread; continue to push the bread to soften it.
Add the heavy cream.
Stir in the breadcrumbs (you may need to add an extra tablespoon or so, to get a firmer consistency).
Add the chopped oysters, 2 big pinches of paprika and a pinch or 2 of the cayenne pepper (depending on how much of a kick you like). Turn off heat.
In a heavy frying pan, fry the bacon until just beginning to crisp; remove from pan and drain on a paper towel.
Fry the remaining mushrooms in the bacon fat until cooked; add to the oyster dressing.
Crumble the bacon and add to the oyster dressing; stir well.
In a separate bowl, mix the eggs together; stir into the dressing.
Butter a casserole dish and pour the dressing mix into it, distributing it and smoothing it out with a spoon.
Bake in a 350° oven until the dressing is set and the top is golden brown.
Let sit a few minutes before serving.