1. Preheat the oven to 350 degrees. Drain the oysters, reserving the liquor. Put the oyster liquor into a 1-cup measuring cup and add enough water, if necessary, to make 1 cup liquid.
2. Bring a large pot of water to a boil with the 2 tablespoons of salt and half the lemon juice. Cook the artichokes until tender, then remove from the water and set aside to cool.
3. Using a spoon, scrape the meat from the tough outer artichoke leaves into a bowl and discard the leaves. Pull off the tender inner leaves and reserve them whole. Remove the fuzzy “choke” from the artichoke bottom, chop the bottom into medium dice, and reserve.
4. In a skillet, melt the stick of butter until it bubbles. Add the flour and cook, stirring often, to form a loose blond roux. Add the green onion and cook until tender.
5. Add the reserved oyster liquor and mushrooms. Bring to a light boil, reduce heat to a simmer, and cook until the mushrooms are tender and the liquid is very thick. Add the oysters and cook for 2 minutes more. Season to taste with Tabasco, salt, and pepper.
6. Scatter the reserved artichoke leaves and meat evenly in a baking dish. Pour the sauced oyster mixture over the artichokes and top with bread crumbs. Dot the top with the remaining butter and bake until the bread crumbs are browned and the rapid bubbling of the liquid contents has begun to slow, 12-15 minutes. Allow to cool for about 5 minutes.