Bring a large pot of water to a boil, and add the sweet potatoes. Cook until tender (20 to 30 minutes), and drain the water.
2 lb. sweet potatoes
Mash the potatoes with a potato masher, add the clarified butter, and season to taste. Set the potatoes aside.
2 lb. sweet potatoes, ½ cup clarified butter, Sea salt and freshly ground black pepper to taste
Melt some cooking fat in a skillet over medium-high heat and cook the sausages until they’re browned on the outside but still uncooked in the middle (about 6 minutes). Remove the sausages from the heat.
Cooking fat
In the same skillet, now over medium heat, cook the carrots, the leek, and the onions until soft (about 8 minutes).
4 carrots, 1 leek, 2 onions
Add the tomatoes, chicken stock, and Worcestershire sauce, if using, and bring to a simmer.
4 cups diced tomatoes, 1 cup chicken stock, 1 tbsp. homemade Worcestershire sauce
Return the sausages and lardons to the skillet and simmer for 30 minutes.
½ lb. bacon lardons, 6 or 8 good quality sausages, Sea salt and freshly ground black pepper to taste
Preheat your oven to 375 F.
Transfer the sausage mixture into an ovenproof dish and spoon the mashed potatoes over it to form a crust.
Place in the oven for 30 minutes and bake until the mash is golden brown.
Let everything rest for a few minutes before serving.