Moist Chocolate Cake (with a secret ingredient that slashes fat!)

 Today is Luke's 1/2 birthday so, of course, I made a cake! And it's a healthy cake to boot.
About the title: This is one of those times when the word "moist" is 100% acceptable! I mean, let's face it, a moist cake is the ultimate goal every time. But why the sweet potato? Not only does the orange tuber add a rich sweetness, it replaces most of the fat in the batter while keeping it moist and tender. Healthy, moist, sweet, chocolatey... What more could we ask for? Someone to make it for us? No need - it's super easy!

So how much sweet potato do you need? About 1 medium. And it should be orange-fleshed, which is also labeled "yam". To get the mash, peel one medium-sized sweet potato and cut it into 2-inch chunks. Place the chunks in a small saucepan and pour over enough water to cover by about 2 inches. Set the pan over high heat and bring to a boil. Boil for 15 minutes, until fork-tender. Drain and mash with a fork. You need 3/4 cup, which is about exactly what you'll get from 1 medium spud.

Moist Chocolate Cake

Cooking spray
1 1/4 cups all-purpose flour
1/4 cup unsweetened cocoa
1 teaspoon baking powder
1 teaspoon baking soda
1/8 teaspoon salt
1/2 cup granulated sugar
1/4 cup vegetable oil
2 large eggs
3/4 cup mashed orange-fleshed sweet potato or yam (about 1 medium)
1/2 cup Greek yogurt or buttermilk
1 teaspoon vanilla extract
1 tablespoon powdered sugar, for dusting over top

Preheat the oven to 350 degrees. Coat a 9-inch round or square cake pan with cooking spray.
In a small bowl, stir together the flour, cocoa, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, beat the sugar and oil together until blended. Beat in the eggs, one at a time. Beat in the mashed sweet potato, yogurt and vanilla.
With the mixer on low speed, gradually beat in the flour mixture. Beat until blended (it's OK if the mixture is slightly lumpy from the sweet potato).
Pour the batter into the prepared pan and bake for 25 to 30 minutes, until a wooden pick comes out clean or with little bits of cake clinging to it (don't worry if the top cracks a little bit, I think that looks cool).
Cool on a rack before dusting with powdered sugar (sift the powdered sugar over top).

Serves 6-8