Chicken-Andouille Casserole

Preheat the oven to 350 degrees F.
In a heavy plastic bag, combine the flour and 1 1/2 teaspoons of the Essence. Add the chicken and toss until well coated. Shake to remove any excess breading and reserve the remaining flour.
In a small bowl, combine the breadcrumbs, remaining Essence, cheese, and butter and set aside.
In a large Dutch oven, heat the oil over medium-high heat. Add the chicken in batches as necessary and cook until browned on each side, about 5 minutes. Transfer to a plate.
Add the sausage and cook, stirring, over medium-high heat until almost browned, about 4 minutes. Add the onions, garlic, and cayenne and cook, stirring, until soft, about 3 minutes. Add the mushrooms and cook until they are soft and give off their liquid, 3 to 4 minutes. Add the reserved flour and cook, stirring, for 1 to 2 minutes. Add the chicken, artichokes, stock, cream, green onions, parsley, and tarragon, stir, and bring to a boil. Sprinkle the bread crumb mixture evenly over the top and bake until bubbly and the top has a golden crust, about 25 minutes.
Remove from the oven and serve hot over toasted French bread.