Prepare the Cake Batter:

• Preheat your oven to 350°F (175°C).
• Grease a large, rimmed baking sheet (approximately 18×13 inches).
• In a medium saucepan, combine 1 cup water, 1/2 cup vegetable oil, 1/2 cup cocoa powder, and granulated sugar. Bring the mixture to a boil, stirring occasionally.
• Remove the saucepan from the heat and immediately stir in the baking soda. The mixture will foam up.
• In a large bowl, sift together the flour and salt. Add the milk and vanilla extract, then pour the foamy cocoa mixture into the flour. Stir until smooth and well combined.
• Stir in the boiling water gradually to achieve a smooth, thin batter.

Bake the Cake:

• Pour the batter evenly into the prepared baking sheet.
• Bake in the preheated oven for 20–25 minutes, or until a toothpick inserted into the center comes out clean.
• Remove the cake from the oven and let it cool slightly while you prepare the icing.

Make the Icing:

• In a medium saucepan over medium heat, melt the butter.
• Stir in 1/4 cup cocoa powder and 1/2 cup milk. Bring the mixture to a gentle boil, then remove from the heat.
• Gradually whisk in the powdered sugar until the icing is smooth and spreadable. Stir in the vanilla extract.
• If desired, fold in chopped pecans or sprinkle them on top after icing.

Assemble and Serve:

• Pour the warm icing over the warm cake, spreading it evenly with a spatula.
• Allow the cake to cool completely before cutting into squares. Enjoy!