4-5 medium to large sweet potatoes, 5/8 cup or 150ml maple syrup or sorgham molasses. 1/2 tsp or 2.5ml chili powder or ground red pepper1/2 tsp or 2.5ml coarse-ground black pepper1/4 tsp or 1.25ml coarse salt1/2 tsp or 2.5ml allspice (can use a half-and-half mixture of cinnamon and nutmeg instead)2 tbsp or 30ml olive, peanut, safflower, sunflower, or canola oil