1Melt butter in a small saucepan over medium heat; cook, whisking constantly, until butter foams and starts to turn golden brown. Place browned butter in a large mixing bowl.
2In a medium mixing bowl, sift together flour, baking powder, baking soda, salt and cinnamon; whisk until combined. Add brown sugar and sweet potato to mixing bowl with browned butter; beat, using a mixer on medium speed, until creamy - about 1 minute. Beat in eggs and vanilla until combined - about 1 minute. Reduce mixer speed to low and gradually beat in flour mixture, alternating with coconut milk until just combined. Stir in pecans until combined.
3Spray a 4 qt. slow cooker with cooking spray. Spread batter evenly into slow cooker; cover and cook on low for 45 minutes. Pour dulce de leche on top, sprinkle with coconut, cover, and cook an additional 1 hour. Turn slow cooker off and allow to cool 45 minutes before serving.