Step 1: Preheat the Oven. Begin by preheating your oven to 350°F (175°C).
Step 2: Prepare Your Cake Pans. Grease your cake pans with butter or cooking spray, and dust them with flour.
Step 3: Mix Dry Ingredients. In a mixing bowl, whisk together the flour, sugar, cocoa powder, and baking soda.
Step 4: Combine Wet Ingredients. In another bowl, mix the mayonnaise, water, and vanilla extract until smooth.
Step 5: Combine Wet and Dry Ingredients. Gradually add the wet ingredients to the dry ingredients, stirring gently.
Step 6: Add Milk and Butter. Fold in the milk and melted butter until the batter is smooth.
Step 7: Incorporate Chocolate Chips. Fold in the chocolate chips and additional vanilla extract.
Step 8: Bake the Cake. Pour the batter into the prepared pans and bake for 30-35 minutes.
Step 9: Cool the Cake. Let the cakes cool in the pans for 10 minutes, then transfer to a wire rack.