1.Use a knife to slice off the bottom 1/2-inch of the artichoke stems, and the top 1-inch of the artichoke globes (the leaves on top). Remove and discard any small leaves toward the bottoms of the stems. Use kitchen shears to trim about 1/4-inch off the pointy tips of each of the artichoke leaves. Rinse the artichokes with water.
2.Preheat oven to 400 degrees. Line a baking sheet with foil and spray with cooking spray. Set aside. Slice the artichokes in half vertically. Use a spoon to scoop out the fuzzy “choke” in the middle of the artichoke. Rub a lemon wedge all over the entire surface of each artichoke half. Place the artichoke halves in a baking sheet cut-side-up. Repeat with the rest of the artichokes.
3.Brush the cut sides of the artichokes evenly with the butter. Then fill the cavities evenly with the garlic, followed by a few small sprigs of the rosemary. Season with salt, garlic powder, and pepper.
4.Flip the artichokes over, using the herbs to help hold in the garlic, so that they are cut-side-down. Brush the tops of the artichokes with olive oil, and season with salt, garlic powder, and pepper.
5.Bake uncovered for 15 minutes. Then remove and cover the pan with aluminum foil, and bake for an additional 25-35 minutes, or until the artichokes are tender and the leaves pull off easily.
6.Place the tray on a cooling rack. Carefully flip the artichokes over and drizzle with lemon juice from remaining wedges. Move to a serving platter and sprinkle with parsley. Serve with lemon garlic aioli.