Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a large bowl, combine flour, sugar, cocoa, baking soda, and salt.

In a separate bowl, mix vegetable oil, vinegar, and vanilla extract.

Add the wet ingredients to the dry ingredients and stir in the cold water.

Mix until the batter is well blended, about one minute.

Divide the batter evenly between the prepared cake pans.

Bake for approximately 35 minutes, or until a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely.

Once the cakes are completely cool, frost them with your choice of frosting.

Stack the two layers of cake on top of each other to create a double-layer cake.

Slice and serve.