Step 1Remove the outer leaves from the artichokes. Cut off the stems and scoop out the chokes. Rub a lemon half over the cleaned artichoke bottoms, then place the bottoms in a bowl of cold water with the juice from the remaining lemon half.
Step 2Bring a medium pot of water to boil. Add the salt, then the artichoke bottoms and simmer until fork-tender, about 15 minutes. Drain and thinly slice.
Step 3Heat the butter in a large skillet over medium heat until melted; continue heating until the butter turns golden brown, about 10 minutes. Add the mushrooms and cook until the mushrooms have softened and released their moisture, about 10 minutes. Add the onions and cook until most of the liquid has evaporated from the skillet, about 5 minutes. Stir in the vinegar and lemon juice. Stir in the crabmeat and season to taste with salt and pepper. Stir in the sliced artichokes and cook gently until heated through, 5 minutes.
Step 4Serve over toast points; garnish the plates with the parsley and lemon wedges.