Mash together butter, garlic confit, and lemon zest. Season with salt. Refrigerate in an airtight container up to 2 weeks, or freeze up to 3 months. (Makes 1/2 cup.)

Halve lemon and squeeze 1 tablespoon juice. Cut second half into wedges. Snap tough outer leaves off artichokes; using a serrated knife, remove top third from each. Trim stems so artichokes stand upright. Rub cut surfaces with juiced lemon half to prevent discoloration.

Set a steamer basket in a large pot. Add enough water to reach just below basket and bring to a boil. Place artichokes in basket, stem-sides up. Cover and steam, adding more water if necessary, until hearts are tender when pierced with the tip of a knife, 25 to 30 minutes. Remove and let cool slightly, about 10 minutes.

Heat garlic with oil in a small pan over medium until fragrant, about 3 minutes. Remove from heat. Add capers, cornichons, and reserved lemon juice; season with salt and pepper. Melt 2 tablespoons garlic butter in small skillet over medium-high heat (reserve remaining garlic butter for another use). Add breadcrumbs and cook, stirring, until golden, about 6 minutes.

Carefully peel back leaves of each artichoke, exposing fuzzy chokes; scoop them out with a spoon. Spoon 1 tablespoon caper mixture into each hollow and sprinkle more between leaves. Divide crumbs among hollows and serve, with remaining sauce and lemon wedges.