Preheat the oven to 350°F and grease two 9-inch pans; line bottoms with parchment.

Melt semi-sweet baking chocolate with water until smooth, then allow to cool slightly.

Cream softened butter with granulated sugar until light; beat in eggs one at a time, then add vanilla.

Whisk together flour, baking soda, and salt. Add dry mix alternately with milk, then fold in cooled chocolate.

Divide batter between pans and bake for 30-35 minutes, until a toothpick comes out with moist crumbs. Cool for 10 minutes then turn out onto a rack.

Melt butter in a saucepan and whisk in granulated sugar and brown sugar until bubbling.

Slowly stir in evaporated milk and cook, stirring until mixture thickens, about 10 minutes.

Temper egg yolks by whisking a small ladle of hot syrup into them, then return to the pan and cook for 2 more minutes.

Remove from heat and stir in vanilla, coconut, and chopped pecans. Let cool until spreadable.

Layer the cakes with the coconut-pecan frosting, spooning generous amounts between layers and on top.

Chill briefly to set before slicing.