Wash sweet potatoes, prick with fork and bake wrapped in foil in 400 degree oven until done, but not mushy. Cool, peel and cut into thick rounds.
Toast walnuts, cool and chop coarsely.
Remove any damaged leaves from endive. Rinse remaining endive and separate leaves, set aside in bowl. Wash and dry parsley.
Slice shallot into thin rounds. Slice bacon into 1/4" pieces.
Heat saute pan over medium heat and add bacon pieces, cook for a few minutes to render fat then add walnut oil and increase heat and cook to crisp bacon, remove from pan and decrease heat and add shallots, cooking until softened. Add sherry vinegar then potatoes and toss to coat.
Combine potatoes with endive and toss to combine. To serve, sprinkle with chopped walnuts, bacon and parsley.