1 cup unsalted butter, melted, slightly cooled, plus more
3 1/3 cups all-purpose flour plus more
1 1/2 lb orange-fleshed sweet potatoes, peeled, cut into large pieces
2 cups sugar
1 tbsp baking soda
1 tbsp ground cinnamon
1 tbsp ground allspice
1 tbsp grated nutmeg
1 tbsp ground ginger
1/2 tsp kosher salt
2 cups chocolate chips
Preheat oven to 350°. Butter and flour pan.
In a medium pot, cover sweet potatoes with water. Bring to a boil; cook until potatoes are soft, about 15 minutes. Drain.
Whisk together flour, sugar, baking soda, cinnamon, allspice, nutmeg, ginger, and salt in a bowl.
Using a stand mixer fitted with paddle attachment, beat cooked sweet potatoes and eggs on medium speed until smooth. Add melted butter and beat until combined. Reduce speed to low, add flour mixture, and mix just until combined. Remove bowl from mixer and, with a wooden spoon, stir in chocolate chips. Spoon batter into prepared pan.
Bake until a toothpick or skewer inserted into center of cake comes out clean, 40-50 minutes. Transfer to a wire rack to let cool completely in pan, about 1 hour. Loosen cake from pan using tip of a dinner knife, then invert a rack over pan and turn cake out onto rack to cool.
Drizzle with chocolate sauce before serving.
10 oz bittersweet chocolate, finely chopped
1 1/2 cups heavy cream
1/2 cup brewed chicory coffee, such as Café du Monde brand
1 cinnamon stick
Put chocolate in a heatproof bowl. In a small saucepan, combine cream, coffee, and cinnamon stick; bring to a simmer over medium heat. Pour hot cream mixture over chocolate.
Let stand, undisturbed, for about 2 minutes. Discard cinnamon stick; whisk until chocolate is completely melted and mixture is blended and smooth.
Cooks’ note: Cake can be made 3 days ahead. Cover with plastic wrap and store at room temperature.