In a small skillet, heat 2 tablespoons olive oil over medium heat. Add the pancetta and cook until browned and fragrant. Scoop out the pancetta with a spoon, reserving the oil, and place it on a paper towel to drain. Add the garlic cloves to the hot oil and cook over medium heat until browned and fragrant. Discard the garlic and reserve the oil.
Tear the bread into chunks and place in a mini-prep food processor. Pulse several times until you have fine breadcrumbs. Set aside.
Place a steamer basket in a large pot and add 2-3 cups of water to the pot. Cover and bring to a boil.
Meanwhile, prep the artichokes: Remove any small leaves on the stem. Peel the stem of the artichokes using a sharp knife or vegetable peeler. Trim the stem keeping about an inch or two on the artichoke. Discard the remnants.
With a sharp knife cut off the top third of the artichoke and discard. Using a pair of kitchen sheers, work around the perimeter of the artichoke, trimming the top third of each of the the spiky petals. Slice the artichoke in half lengthwise. Use a spoon (even a sturdy measuring spoon will work) to remove the hairy choke and purple interior. Rub or squeeze lemon juice from over the interior of the artichoke to prevent browning. Continue with the remaining artichoke halves.
When the water is boiling, place the artichokes, cut side down onto the steaming tray and steam them for 25-40 minutes, depending on your artichoke. Check doneness by how easily one of the petals can be pulled from the bottom of the vegetable. When artichokes are cooked, remove them from the heat and carefully transfer them to a cutting board with a pair of tongs. Pat the artichokes dry with paper towels.
Spray a baking dish with vegetable spray and lay the artichoke halves, cut side up, in the dish. Drizzle with the remaining tablespoon of olive oil.
Preheat the broiler.
In a medium bowl combine the fresh breadcrumbs, parmesan cheese, pancetta, capers, reserved oil from the skillet and lemon zest. Toss until thoroughly combined.
Carefully fill the artichoke cavity with the breadcrumb mixture. Place the artichokes under the broiler for 3-5 minutes until the filling is golden brown. Serve.