Step 1

Preheat the oven to 350°F (180°C) and butter a 12x17-inch (30x43cm) sheet pan. Set aside.

Step 2

In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking powder, and salt.

Step 3

In a separate measuring cup, combine the eggs, water, buttermilk and vegetable oil.

Step 4

Stir the wet ingredients into the dry until the batter is smooth and pour the batter into the prepared sheet pan.

Step 5

Bake for 20-25 minutes, until a toothpick inserted into the center, comes out clean. Let cool for 10 minutes.

Step 6

After the cake has cooled slightly, make the frosting: combine the sugar, evaporated milk, and melted chocolate in a blender and blend until combined and thickened, about 30 seconds.

Step 7

Pour the frosting over the cake, sprinkle all over with the pecans and let the cake and frosting cool for a few hours before slicing. Store the cake at room temperature for up to 3 days.