Place a steamer basket in an extra large pot with a lid and fill with about 1 inch of water fill to just the bottom of the steamer basket. Bring water to a boil. When water is boiling, carefully arrange artichokes, stem end up, in the steamer. Squeeze the juice of one lemon over the artichokes. Quarter the juiced lemon rind and place the sections in any spaces between the artichokes. Cover and cook for 35 to 45 minutes, until tender when pierced in the stem end with a fork. Remove artichokes to large plates and spread open the petals. Use a small spoon with a pointed tip as opposed to rounded to scoop out the purplish and pale green center leaves and the hairy choke beneath it. Be sure to remove all of the hairs.

While artichokes are cooking, combine hazelnuts, bread crumbs and garlic in a dry saut pan and toast over medium heat for about three minutes, until it starts to brown, stirring constantly. Let cool. Mix all of the remaining ingredients except for the lemon, olive oil and mayonnaise together in a bowl. Before serving, add the toasted nuts and bread crumbs, 3 tablespoons juice from the remaining lemon, olive oil and mayonnaise to the bowl and combine. Spoon about two tablespoons of gremolata into the center of each artichoke and serve.