In a large pot, saute chopped carrot, onion, celery and fresh mushrooms in 2 tablespoons of butter for 5 minutes or until the onions are transparent.
In another large pot, melt 1/2 cup butter and stir in the flour. Cook for 5 minutes.
Whisk in the chicken broth to the flour mixture. Add the sauteed vegetables, artichokes hearts, bay leaf, salt, cayenne pepper, thyme, oregano and sage. Simmer for 30 minutes over medium heat.
Whisk in cream and add oysters; bring to a simmer, but do not boil.
Preheat the oven to 450 degrees F (230 degrees C). Butter a shallow baking dish.
Combine the bread crumbs and cracker crumbs, stir in the melted butter. Place a thin layer of the crumb mixture in the bottom of the prepared baking dish. Layer the oysters over the crumbs and sprinkle with salt and pepper to taste. Pour 2 tablespoons oyster liquid and 1 tablespoon milk over the top. Repeat then cover the top layer with the remaining crumb mixture.
Bake at 450 degrees F (230 degrees C) for 30 minutes.