Preheat oven to 400F. Wash sweet potatoes and carefully poke holes in each potato using a fork or knife. Bake for about 1 hour or until potatoes are fork tender. Turn oven heat down to 350F.
Let potatoes cool and then remove skin. Add to a large bowl with the rest of the ingredients and mix until fully combined.
Lightly coat baking dish with oil. Add sweet potato mixture into your dish and smooth out the top.
Add all of the crumble ingredients to a bowl and mix using a fork or your hands. Spread crumble mixture over sweet potatoes.bake 30-40 mins or until edges begin to set.