6 thin slices of prosciutto (2 1/2 ounces), coarsely chopped
1 teaspoon finely grated lemon zest
1 1/2 tablespoons fresh lemon juice
Salt and freshly ground black pepper
2 tablespoons chopped parsley
Crusty bread, for serving
With a serrated knife, cut off the top thirds of the artichokes. Snap off the small leaves from the artichoke bottoms. Cut the artichokes in half lengthwise. With a spoon, scrape out the hairy chokes and rub the artichokes all over with the lemon half.
In a skillet, heat the 1/4 cup of olive oil. Add the garlic and shallots and cook over moderate heat until golden and softened, about 7 minutes. Add the tomatoes and cook until starting to soften, about 2 minutes. Add the wine and boil over high heat for 3 minutes. Add the stock and bring to a boil.
Transfer the contents of the skillet to a large slow cooker set on high. Nestle in the artichokes, cut sides down, and add the thyme and sage sprigs. Cover and cook for 45 minutes. Reduce the heat to low and cook for 1 hour and 45 minutes. Turn the artichokes cut sides up and cook for 45 minutes longer, until tender. Discard the thyme and sage sprigs.
Meanwhile, in a small skillet, heat the remaining 1 tablespoon of olive oil. Add the chopped prosciutto and cook over moderate heat, stirring, until crisp, about 2 minutes. Remove from the heat and stir in the lemon zest, lemon juice and the parsley.
Season the artichokes with salt and pepper. Transfer to 4 shallow bowls. Scatter the prosciutto over the artichokes and into the cooking juices and serve with crusty bread.
The braised artichokes and the prosciutto mixture can be refrigerated separately for up to 3 days. Reheat gently.