In a large saucepan combine butter, sweetened condensed milk and brown sugar.
Heat over medium heat until butter is melted and brown sugar is dissolved. Stir often.
Lower heat to medium-low and add the egg yolks to the saucepan, stirring until the eggs are fully incorporated.
Continue heating the mixture on medium-low heat, stirring frequently, until thickened (approximately 8 minutes).
Remove from heat and transfer mixture to a large, heatproof bowl.
Add coconut and toasted pecans and stir well.
Allow icing to cool completely before using (approximately 45 minutes).
Chocolate Cupcakes
Preheat oven to 350°
Line cupcake pan(s) with paper cupcake liners (18 total cupcakes)
Combine flour, cocoa powder, sugar, cornstarch, baking powder and baking soda in the bowl of a stand mixer. If mixing by hand or with a hand mixer, combine ingredients in a large mixing bowl.
Add oil and eggs. Mix until combined.
Slowly pour brewed coffee into bowl while continuing to mix, scraping the bowl occasionally. The batter should be smooth.
Pour the batter into the cupcake liners filling approximately ⅔ full.
Bake for 18 - 22 minutes or until cupcakes are fully risen and a toothpick inserted in the center of a cupcake comes out clean.
Place cupcakes on a rack and allow to cool completely before icing. Spread frosting on top of each cupcake and enjoy!