1. Preheat oven to 350 F. Grease a 9x13-inch baking pan; set aside. In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt.
2. Add coconut oil, yogurt, melted chocolate, eggs, vanilla, and water. Stir together until combined.
3. Pour batter into prepared pan.
4. Bake for 30-40 minutes, or until a toothpick inserted in the center comes out clean.
5. Let cool in pan to room temperature. To make frosting, beat butter until smooth, about 1-2 minutes.
6. Add coconut milk, powdered sugar, and vanilla extract. Beat until well-combined. Stir in pinch or two of salt, to taste.
7. Spread frosting over cooled cake, and top with coconut chips. Store any leftovers covered in the fridge.