Lamb Shanks and Potatoes

3 tablespoons tomato paste

2 tablespoons apricot jam

6 garlic cloves, thinly sliced

3 strips orange zest

3/4 teaspoon crushed dried rosemary

1/2 teaspoon ground ginger

1/2 teaspoon ground cinnamon

Coarse salt and ground pepper

3 1/2 pounds lamb shanks, trimmed of excess fat and cut into 1 1/2-inch-thick slices

1 1/4 pounds small new potatoes, scrubbed well, halved (or quartered, if large)