How to Make It
Preheat oven to 375°F. Coat a 1-quart round soufflé dish with 1 tablespoon of the butter. Microwave remaining 7 tablespoons butter in a small microwavable bowl on HIGH until melted, about 30 seconds. Let cool 3 minutes.
Stir together eggs, sweet potatoes, evaporated milk, salt, vanilla, pumpkin pie spice, 3/4 cup of the brown sugar, and 4 tablespoons of the melted butter in a large bowl until completely smooth. Pour batter into prepared soufflé dish; bake in preheated oven until beginning to set, about 30 minutes.
Meanwhile, stir together coconut, flour, pecans, and remaining 1/4 cup brown sugar and 3 tablespoons melted butter in a bowl until just combined. (Mixture will still be clumpy and coarse.)
Remove soufflé from oven; top evenly with coconut-flour mixture. Return to oven; bake at 375°F until golden brown, about 30 minutes. Let cool slightly, about 10 minutes. Serve warm.