Preheat the oven to 350 F and lightly grease a 2 quart casserole dish with canola oil. I wipe a bit on with a paper towel. Peel and then boil sweet potatoes until tender. Mash the sweet potatoes with the margarine until smooth. Add the milk, vanilla, maple syrup, sea salt, nutmeg and cinnamon. Pour into casserole dish. Next, mix the topping ingredients together until well-combined. Sprinkle topping mixture over the casserole and bake for approx. 50 minutes, checking it every so often. Serves 7-9.