Scatter the onions, carrots, celery, garlic, rosemary and thyme around the ducks.

Scatter the sliced onions, garlic and carrots in the bottom of a large roasting pan.

Scatter the shallots, parsnips, potatoes and carrots over the bottom of a large roasting pan.

Bake for 10 minutes longer and scatter the celery, thyme, carrots and onions over the bones.

Brush with oil, and scatter the onions, celery, carrots, garlic, bay leaf and thyme over the meat.

Scatter the jicama and carrots over the crab and serve immediately.