I adapted another stuffed artichoke (one that uses bread crumbs) by Giada De Laurentiis to make this recipe. Although there is an alternate microwave method included in this adopted recipe, I recommend using Giada's stovetop method.
Fill a large pot (a stock pot works well) with cold water; roll the lemon on the counter with your palm to "loosen" juices, then cut in half and squeeze the juice into the pot of water and toss in the squeezed lemon halves.
Trim the artichokes: cut off the top quarter from the artichokes and discard, remove the bottom and tough outer layer of stem, snap off the tough outer leaves from the base, remove dark green areas of the base.
Cut artichokes in quarters and remove the choke and small purple leaves.
Add trimmed and quartered artichokes to the pot of water, cover, and simmer over medium heat until tender, about 45 minutes; drain and set aside to let cool.
(Microwave method: cut off stems and loose outer leaves from artichoke. Cut of 1-inch from tops. Snip off sharp leaf tips. Brush cut edges with lemon juice. Place artichokes and water in a casserole. Cover with vented clear plastic wrap. Microwave, covered, on 100% power for 7 to 9 minutes or just till tender, rotating casserole a half-turn after 4 minutes. Let stand, covered, while preparing stuffing.)
In a skillet over medium heat, melt the butter; saute the green onion and carrot for 5 to 7 minutes, until vegetables begin to brown.
Stir in the ground sage, coating the vegetables well.
Add the cooked rice and stir well, and saute for an additional 5 minutes; remove from heat.
Preheat oven to 350 degrees F.
Place artichoke quarters in a lightly buttered baking dish.
Spoon rice stuffing onto each artichoke, sprinkle with Parmesan cheese.
Bake at 350 degrees F for 10 minutes, until the Parmesan browns a little.
Meanwhile, prepare the sauce: in a saucepan stir together the chicken broth, 2 teaspoons lemon juice, cornstarch, and white pepper. Heat over medium temperature for about 5 minutes or until thickened and bubbly.
In another bowl, whisk HALF of the hot sauce mixture into the egg yolk, combine well; then return the yolk mixture into the remaining sauce mixture and simmer for about 2 to 3 minutes to desired consistency. Check sauce for any possibly needed additional salt and pepper.
Transfer stuffed artichokes to a warm serving platter.