Method:
Heat canola oil in a heavy skillet or Dutch oven over medium heat. Add leeks and cook, stirring often, until tender, about 15 minutes. Add garlic, rosemary, sage, pepper flakes, celery and prosciutto and cook for 5 minutes more, or until soft. Add lamb and cook, stirring occasionally, until browned. Add wine, increase heat to high and cook for about 5 minutes. Add broth and tomato paste and stir well. Continue cooking at a simmer over a low flame for 45 minutes, or until lamb is tender.
Add artichoke hearts and cook for 5 minutes. Stir in zest, lemon juice, salt and pepper, then sprinkle parsley over the top of the stew and drizzle with olive oil. Stir well, then serve.