Instructions

1. Cook the batatas and make the custard:
2. Cut 4 tablespoons of the unsalted butter into 4 pieces and let sit at room temperature to soften while you prepare the rest of the casserole.
3. Arrange a rack in the middle of the oven and heat the oven to 350°F. Melt the remaining 1 tablespoon unsalted butter. Brush a 9x13-inch baking dish with the melted butter.
4. Bring 4 quarts water to a boil in an 8-quart pot over medium-high heat. Meanwhile, peel and cut 5 1/2 pounds batata into 1-inch chunks.
5. Add the batata to the boiling water and reduce the heat to medium. Simmer, stirring occasionally, until fork-tender, 15 to 20 minutes. Meanwhile, prepare the coconut milk custard and pecan-coconut topping.
6. Place 3 large eggs in a large bowl and whisk until smooth. Add 1 can coconut milk, 3/4 cup packed brown sugar, 1 teaspoon ground cinnamon, 1 teaspoon vanilla extract, salt, 3/4 teaspoon ground ginger, and 1/4 teaspoon ground allspice, and whisk until combined.
7. Make the pecan-coconut topping:
8. Place 1 cup chopped pecans, 1/2 cup sweetened coconut flakes, 1/2 cup packed brown sugar, 1/4 cup all-purpose flour, 1/4 teaspoon kosher salt, and 1/8 teaspoon ground allspice in a medium bowl. Toss with your hands to combine.
9. Melt 5 tablespoons unsalted butter in the microwave or on the stovetop. Pour into the pecan mixture and use your hands or a rubber spatula to toss until a thick, crumbly topping forms.
10. Assemble the casserole:
11. When the batata is ready, drain and return it to the now-empty pot. Add the softened butter and mash with a potato masher until the butter is melted and the mixture is smooth. Add the coconut milk mixture and stir until absorbed and the mixture is smooth again.
12. Transfer the mixture into the baking dish and smooth the top with a rubber spatula. Sprinkle with the pecan-coconut topping, breaking up the mixture with your fingers as needed.
13. Bake until the topping is a deep golden-brown and crisp on top, about 30 minutes. Let cool for 10 minutes before serving.