Buttered Rum and Candied Sweet Potato Crumb Cake

Directions

1. 1
   For the Streusel:In a medium bowl, whisk together the flour, graunlated sugar, brown sugar and cinnamon. Slowly stir in the melted butter with a fork, letting it coat the dry ingredients until crumbs are formed.Pinch pieces together to form more crumbs. Set aside.For the Cake:Preheat the oven to 350F. Prepare a9x13 inch baking pan by greasing with butter and lining the bottom with parchment paper, if you wish. You can also use non-stick baking spray.In the bowl of an electric stand mixer fitted with the whisk attachment, beat the egg whites on high speed until stiff peaks form.
2. 2
   Transfer the whipped egg whites to a small bowl and place in the refirgerator.Clean your stand mixer bowl and whisk attachment. Beat the graunlated sugar and oil on medium-high speed until combined.
3. 3
   Add the egg yolks 1 at a time, combining well after each addition and scraping downt he sides and bottom of the bowl as needed.
4. 4
   Add the sweet potatoes, hot water and vanilla extract and beat for another 3-4 minutes.Turn your mixer down to its lowest speed and carefully add the flour, baking powder, cinnamon, cloves, salt, baking soda and nutmeg.
5. 5
   Mix the batter until just combined. Be care not to overmid.
6. 6
   Remove the egg whites from the refrigerator and gently fold them into the batter.
7. 7
   Pour half of the batter into the prepared baking dish. Cover with half of the streusel. Repeat with the remaining batter and streusel.
8. 8
   Bake for about 55 minutes, or until a toothpick inserted into the center of the cake comes out moist but mostly clean.
9. 9
   Let the cake cool in the pan for 10 minutes. Using a toothpick, poke the top of the cake in various locations. Lightly cover the cake with foil or plastic wrap so it does not dry out. While the cake continues to cool, prepare the sauce.For the Butter-Rum Sauce:In a medium saucepan over medium heat, bring the granulated sugar, butter, rum and water to a boil. Once it is at a boil, whisk the sauce until it thickens, about 3-5 minutes. When the sauce can thickly coat the back of a spoon, remove from the heat and let cool for 10-15 minutes.
10. 10
    Pour the sauce over the warm cake.
11. 11
    Serve at room temperature.