Sweet Potato Bundt Cake with Maple Glaze

Position rack in bottom third of the oven; preheat to 350℉. Generously coat a large Bundt pan with cooking spray.

To prepare cake: Sift cake flour, all-purpose flour, oat flour, baking powder, 3/4 teaspoon salt, cinnamon, baking soda, ginger, white pepper, cardamom, allspice and nutmeg into a large bowl. Combine granulated sugar, brown sugar and oil in another large bowl; beat with an electric mixer on medium speed until well combined, 1 to 2 minutes. Add eggs, one at a time, beating well after each addition. Add mashed sweet potatoes and vanilla, beating on medium speed until thoroughly combined. 

Add half of the dry ingredients to the wet ingredients; mix on low speed until well combined. With the mixer still running, slowly pour in buttermilk and mix until combined. Add the rest of the dry ingredients and mix until there are just a few streaks of flour. Do not overmix. Fold in pecans with a large rubber spatula, being sure to scrape the bowl so that there are no streaks of unmixed flour.

Scoop the batter into the prepared pan, being sure to fill all the grooves, and smooth the top as best you can with a small offset spatula. Bake until a toothpick inserted into the center of the cake comes out with just a few crumbs, being sure to test in three spots, 50 to 60 minutes. Cool in the pan on a wire rack for 10 minutes, then carefully turn out onto the rack to cool for 20 to 30 minutes more.

To prepare glaze: Combine maple syrup and butter in a small saucepan; cook over medium heat, stirring occasionally, until the butter is melted. Remove from the heat; whisk in 1/2 cup confectioners' sugar and salt until smooth. Gradually whisk in the remaining 1 cup confectioners' sugar until smooth.

Spoon or pour the warm glaze over the still-warm cake. Sprinkle with more pecans, if desired, pressing gently to adhere them to the glaze. Let the cake cool completely, about 1 hour, before slicing and serving.