Preheat the over to 375 degrees.2. Toss the bread cubes with 4 sage leaves, rosemary, garlic, olive oil, salt and pepper. Spread on baking sheet and bake until golden and toasty. Remove from oven and put in large bowl or container. (They are great for a little snack as you continue with the recipe.)3. In a large pan, saute the chorizo in a little olive oil until golden. The chorizo is already cooked but it's nice to render the fat and get it a little crispy. Remove chorizo with a slotted soup to the bowl with the bread.4. Next, saute the mushrooms in the chorizo fat (adding a little olive oil if necessary) and add salt and pepper to taste. Remove to bowl with bread.5. Next, add some olive oil as the mushrooms most definitely sucked up all the fat. Saute the onion until soft and golden and add salt and pepper to taste. Add to the bowl with the bread.6. Lastly, saute the sweet potato (adding oil as necessary) and salt and pepper to taste. You don't need to cook the potato through as it will cook in the oven but it's good to get a little color on it.7. Whisk 2 cups of stock or broth with the egg and salt and pepper. Pour into the bowl of bread, etc., add the remaining sage, 2 tablespoons of the fat, and toss thoroughly until evenly moistened. You may need to add up to an additional 1/2 cup of stock but don't overdo it. You have been seasoning all along but you may want to taste for seasoning and adjust the salt and pepper.8. Pour into a baking dish — a 9x13 or an oval gratin pan. Cover and refrigerate for at least an hour. This allows the bread to really absorb the stock and makes for a moist interior and crunchy top.9. Bake covered for 30 minutes. Remove foil, brush top with remaining 2 tablespoons of fat, and bake for 15 more minutes. You may want to broil the top for the last few minutes so the top gets nice and crispy but be sure to watch it carefully.