Drain the artichoke hearts and add to a shallow baking dish. Add the olive oil, garlic, and red pepper flakes. Toss to coat. Top with the lemon slices and rosemary.
Roast for 25-30 minutes until golden brown, stirring once half-way through roasting.
Meanwhile, prepare the breadcrumb topping. Add the sandwich roll or bread to a food processor. Pulse for 3-5 seconds until the bread turns to small crumbs. Add the oil and parsley and pulse once or twice to combine. Set aside.
Remove the artichokes from the oven and sprinkle with the breadcrumb topping. Bake for another 5 minutes. Remove and serve. (Optional: remove the garlic cloves before serving to tame the garlic flavor.)