Instructions:

Preheat your oven to 350 degrees Fahrenheit. Prepare your cake pans by greasing them to prevent sticking.

In a large bowl, sift together the flour, cocoa powder, and granulated sugar. This helps to aerate the dry ingredients and guarantees a smooth batter.

In a separate bowl, combine the mayonnaise, water, and vanilla extract. Mix well until smooth.

Gradually add the wet ingredients to the dry ingredients, stirring gently until just combined. Be careful not to overmix, as this can affect the cake's texture.

Pour the batter evenly into the prepared pans. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

While the cake is baking, prepare the frosting. In a mixing bowl, combine the softened butter (or cream cheese) and cocoa powder until smooth.

Alternately add the powdered sugar and milk to the butter mixture, beating until you reach a spreadable consistency. Finally, mix in the vanilla extract.

Once the cake is baked and cooled, frost the top and sides with the prepared frosting. Mayonnaise adds moisture to the cake, enhancing flavor and texture.

Store the frosted cake in the refrigerator, covered, for 3-4 days for peak freshness.

For extra tips, consider using high-quality cocoa powder for a richer chocolate flavor, and always verify your ingredients are at room temperature before mixing for the best results.

If you want to add some flair, consider incorporating chocolate chips or nuts into the batter, or top the finished cake with fresh berries for a pop of color and flavor. Enjoy your baking!