In a large frying pan over medium-high heat, fry the bacon until crisp; drain. Crumble into a large bowl and add bread crumbs, Parmesan cheese, Romano cheese, green onions, parsley, garlic, salt, black pepper, and cayenne pepper; toss to combine.
Cut about 3/4-inch off the tops of each artichoke. With your scissors, snip off the pointed ends of each artichoke leaf. Wash under cold, running water. Pull off lower petals and cut off stem. Rub a lemon on the cut ends to prevent browning. Slice off the stem end of each artichoke so that they sit up straight. Spread the leaves of each artichoke as much as possible.
Pack in a generous amount of bread stuffing in each prepared artichoke. Tap each artichoke gently to let any loose stuffing fall off. Stand them in a casserole or roasting pan just large enough to hold them in a single layer. Add water to a depth of 1 1/2 inches.
Pour a generous amount of olive oil over each artichoke, letting it seep in. Top each artichoke with a slice of lemon. Bring the water to a boil, cover, reduce heat to let and steam the artichokes approximately 1 hour (depending on size of artichokes) or until the leaves pull off easily. Test for doneness by pulling out a leaf and tasting for tenderness. Check the water level after about 25 minutes, and add more if necessary.
Serve hot or at room temperature. The stuffed artichokes can be prepared in advance and reheated before serving. Any leftover stuffing keeps for 2 weeks in the refrigerator and longer in the freezer.
Option: Sprinkle grated Parmagiano Reggiano cheese over the top and place briefly under a broiler until cheese melts and begins to brown.
Makes 6 servings.