Put the flour in a large mixing bowl and season with Essence. Season the shanks with Essence, add the flour, and toss to coat evenly. Tap off any excess.
Heat the olive oil in a Dutch oven over medium heat. Add the shanks and sear for 4 minutes on each side. Add the onions and mushrooms, season with salt and pepper, and cook, stirring often, for 2 minutes. Add the wine, stock, garlic, and herbs and season with salt and pepper. Bring to a boil, cover, reduce the heat to medium-low, and simmer for 1 hour. Add the potatoes, season with more salt and pepper, and simmer until the meat begins to fall off the bones, 30 to 40 minutes. Remove the bay leaves.
Transfer the shanks and gravy to a large shallow bowl. Garnish with the green onions and serve hot.
Yield: 4 servings