Preheat your oven to 350°F (175°C) and prepare three 8-inch (or two 9-inch) round cake pans by greasing them with butter or vegetable oil and lining the bottoms with parchment paper.

In a medium mixing bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, baking powder, and a pinch of salt. Set aside.

In a large mixing bowl, beat together the granulated sugar, vegetable oil, eggs, and vanilla extract until smooth.

Slowly add the dry ingredients to the wet ingredients, alternating with the buttermilk. Mix until just blended and then stir in the hot water or coffee.

Divide the batter evenly among the prepared pans and bake for 25-30 minutes or until a toothpick comes out clean. Allow to cool in the pans.

In a medium saucepan over medium heat, combine brown sugar, evaporated milk, unsalted butter, and egg yolks. Stir continuously for 10-12 minutes until thickened.

Stir in the shredded coconut and chopped pecans. Allow the frosting to cool slightly.

Assemble the cake by placing a layer on a serving plate, spreading frosting between layers, and covering the top and sides with frosting.

Slice and serve your decadent German chocolate cake to eager guests!