Pre-heat oven to 350 degrees F.
Heat 1 tablespoon of olive oil in a large non-stick fry pan. Once heated, place diced shallot and celery in oil. Stir for a couple minutes until the celery becomes translucent and the shallot softens.
Toast the walnuts in a small non-stick pan until browned and they start to give off a smell.
Add the 3 cups of diced sweet potatoes to the pan and cook, stirring every few minutes for about 10-13 minutes or until the sweet potatoes start to soften.
Then add the sliced brekkie links and cook for another five minutes to heat the links through. Add the mixture to a large baking dish.
While sweet potatoes cook, in a separate non-stick fry pan over low-medium heat, cook the sliced apples for a couple minutes and then sprinkle them with 1 tablespoon of brown sugar. Turn over in the pan to coat. Add ¼ cup of apple juice and cook about 5 minutes. Sprinkle with a little salt and remove from heat.
Top the sweet potatoes with the cooked apple slices, sprinkle with the walnuts and drizzle the 1.5 tablespoon of maple syrup over top.
Bake in a pre-heated oven for 20 minutes. Serve.