Beef tagine with sweet potatoes, peas, ginger, & ras-el-hanout

Ghee	2 tablespoons
Ginger, peel, finely chopped	1 ½-inch piece
Onion, finely chopped	1
Beef, lean, cut into bite-sized cubes	2 pounds
Ras-el-hanout	1 ½ tablespoons
Potatoes, sweet, peeled, cubed	2
Peas	1 pound
Tomatoes, skinned, seeded, chopped	2
Lemon, preserved, finely chopped	1
Cilantro, finely chopped	1 bunch
Salt, sea
Pepper, freshly ground
Yogurt, plain

1. Melt the ghee in the tagine base over medium heat. 
2. Add the ginger and onion, and sauté until soft. 
3. Toss in the beef, and sear on all sides, and then stir in the ras-el-hanout. 
4. Pour in enough water to just cover the meat, and bring to a boil. 
5. Reduce the heat, cover, and cook gently for 40 minutes. 
6. Add the sweet potatoes, season with salt and pepper, cover, and continue to cook for 20 minutes, until the meat is tender. 
7. Toss in the peas and tomatoes, cover, and cook for 5 to 10 minutes. 
8. Sprinkle with preserved lemon and cilantro, and serve immediately with bread and yogurt. 

Recipe from Tagines & Couscous by Ghillie Basan.