Preheat your oven to 350°F (175°C). Grease and line two 8-inch round cake pans.
In a large bowl, mix flour, sugar, cocoa powder, baking powder, baking soda, salt, and instant coffee.
Add milk, oil, eggs, and vanilla. Beat until well combined.
Stir in boiling water until the batter is smooth. The batter will be thin.
Pour the batter evenly into the prepared pans.
Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean.
Let cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely before frosting.