Season lamb shanks generously with sea salt and freshly ground black pepper.
Dredge lamb shanks in flour-paprika and set on a plate.
Heat 3 tablespoons of the olive oil over medium-high heat in a large paella or other frying pan with a tight-fitting ovenproof cover.
When the oil is shimmering and easily coats the bottom of the pan, add the shanks and brown on each side until golden - about 3-5 minutes per side.
Remove shanks from the pan and set aside on a plate.
Add the mirepoix - onions, carrot, and celery - and sauté for about 5 minutes to soften the vegetables.
Add wine, 1 cup crushed tomatoes, and citrus zests to the pan. Stir, and bring to a simmer; cook about 5 minutes, until somewhat thickened.
Meanwhile, tie together thyme sprigs, rosemary and bay leaves to make a bouquet garni.
Add to the pan along with the stock. Stir, and bring to a simmer.
Add lamb shanks, cover the pan, and place in the oven. Braise (covered) for about 3 hours, turning shanks every half hour, until lamb is completely tender.
After 2 1/2 hours, add the pitted olives.
After the three hours, remove lamb shanks to a warmed plate and cover with foil.
Remove bouquet garni and discard.
Bring pan with sauce to a simmer. Skim off as much fat as possible.
Add remaining 1 cup crushed tomatoes and reduce heat until sauce thickens.
Serve lamb shanks on polenta or mashed potatoes with a good helping of the sauce on top.
Serve immediately.
Notes
Note: In France, ask your butcher for becquets d'agneau (also known as souris d'agneau)