Sweet Potato Filling:
3 1/2 pounds of sweet potatoes peeled and cut into 1-inch chunks
1/2 cup of heavy cream
1/3 cup of packed brown sugar
1 tablespoon of unsalted butter
1 teaspoon of vanilla extract
1/4 teaspoon of coconut extract
1 egg lightly beaten
1 teaspoon of sea salt
1/2 cup of all purpose flour
1/2 cup of sweetened coconut flakes
1/3 cup of rolled oats
1/4 cup of macadamia nuts chopped
1/4 cup of packed brown sugar
1/4 cup of cold unsalted butter cut into small dice
Preheat the oven to 375°F. Lightly oil a 9-inch square-baking dish.
Combine the sweet potatoes with enough water to cover by 2-inches in a large saucepan over medium-high heat. Bring to a boil and cook until the potatoes are very tender, 12-15 minutes. Drain and transfer to a large bowl.
Meanwhile, combine the cream, sugar, butter, vanilla extract, coconut extract, egg and salt in a bowl. Add mixture to the potatoes and beat with an electric mixer on medium until smooth. Transfer to the prepared baking dish.
For the topping combine the flour, coconut flakes, oats, nuts and sugar in a bowl. Add the butter and work it into the flour mixture with your fingers until you can form it into clumps. Sprinkle the mixture over the sweet potatoes.
Bake in the center of the oven, covered, for 20 minutes. Uncover the casserole and bake until heated through and the top is browned, about 20-22 minutes longer. Let stand 10 minutes before cutting.