This is more like a chocolate cake so I added chopped almonds in the ingredients.
1 cup all-purpose flour
1/2 cup cocoa powder, sifted to remove lumps
3/4 cup sugar
1 teaspoon baking soda
1/2 teaspoon salt
5 tablespoons melted butter, olive oil or vegetable oil
1 teaspoon vanilla
1 cup buttermilk (or 1 tablespoon of white vinegar + milk to make up 1 cup)
2 teaspoons instant coffee, dissolved in 1 tablespoon hot water (or one espresso shot)
Preheat oven to 350F
Measure dry ingredients in a large bowl. Stir with a whisk or fork to combine.
Measure wet ingredients in a small bowl. Stir to combine.
Pour wet ingredients into dry ingredients, all at once. Stir with a spatula or spoon, just until all the dry ingredients are moistened.
Pour the batter into a greased 8″ square pan or a 11″x7″ rectangular pan.
Bake for 25 to 30 minutes, or just until the top springs back when lightly touched.
Cool on rack. This may be hard to remove from the pan unless totally cooled.