Arrange a rack in the middle of the oven, remove any racks above that rack, and heat the oven to 350°F (180°C). Scrub 3 lbs of sweetpotatoes and pierce all over with a knife or fork.

Place the sweetpotatoes directly on the oven rack (place a sheet of aluminum foil onto a lower rack, but never onto the bottom of the oven, if you’re worried about drips). Bake until tender, about 1 ½ hours.

Remove the sweetpotatoes from the oven and let cool until they are ok to handle, about 30 minutes. Halve each sweetpotatoe lengthwise, then scoop the flesh into a bowl; discard the peels.

To make the topping, melt the butter then remove from the heat and stir in the walnuts and almonds. Mix until all of the nuts are coated. Add 1/4 cup packed light brown sugar, 2 TBSP all-purpose flour, the orange zest, and 1/8 tsp kosher salt, then toss to combine.

Coat a 2-quart soufflé dish or 8-inch square, 2-inch-high baking dish with softened butter.

To make the souffle base, place the eggs, half-and-half, brown sugar, 2 TBSP of the freshly squeezed orange juice, kosher salt, cinnamon, and ground nutmeg in a food processor fitted with the blade attachment. Process or blend until smooth and the sugar is mostly dissolved, about 30 seconds.

Add the reserved sweetpotato and process or blend until very smooth, about 30 more seconds.

Add the almond flour and baking powder then process just until combined, about 10 seconds. Do not overmix.

Transfer the puree to the prepared baking dish and spread into an even layer. Sprinkle evenly with the citrus-infused nutty topping.

Bake until puffed and just set in the middle, 45 to 55 minutes. Let cool for about 5 minutes before serving.