Preheat your oven to 350 degrees. Line one muffin tin with paper liners. Set aside.
Whisk together the cocoa and warm water until smooth. Set aside.
Whisk flour, baking soda, baking powder, and salt in a medium sized bowl. Set aside.
Melt the butter and sugar in a medium sauce pan over low heat. Transfer to a mixing bowl & beat for several minutes until the butter is completely cooled.
Add the eggs, one at a time, to the butter mixture. Stir until incorporated.
Stir in the vanilla and cocoa mixture until combined.
Turn the mixer speed to low. Add the dry ingredients and sour cream. Stir until all ingredients are blended.
Fill cupcake liners 3/4 full. Bake 20 minutes or until a toothpick comes out clean. Cool completely.
Remove the labels from the two cans of sweetened milk. Place the cans on their side in a large pot. Cover completely with water.
Bring the pot to a boil. Reduce the heat and simmer for two hours. (SEE NOTES)
Leave your cans in the hot water and allow to cool completely.
Toss the coconut and pecans in a medium sized bowl.
Once your cans have cooled, remove from the water and carefully open. Stir into the coconut mixture.
Spoon over your cooled cupcakes.
It is VERY important that you make sure you keep the cans of sweetened condensed milk completely submerged in water while cooking. Allowing any part of the can to be exposed could result in the can erupting and potentially harming you or your kitchen. It is completely ok to add water as needed.
Allow the cans to cool completely before opening.
Be safe and enjoy!