Preheat oven to 350°F and grease a 9×13 casserole dish.
Peel and chop the sweet potatoes into large chunks. Place in a large saucepan and cover with water, bring to a boil and reduce to simmer until the sweet potatoes tender. Drain and let cool.
In a bowl, combine the pecans, oats, oat flour and brown sugar. Cut in butter until the mixture is sandy. Set aside.
Mash sweet potatoes in a large bowl with a fork, then add remaining ingredients for base. Mix until combined.
Spoon the sweet potato mixture into the casserole dish and sprinkle topping. Bake uncovered for 40-45 minutes until the top is golden brown.
Now you're cooking with milkadamia!
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