Chocolate Mayonnaise Cake

I saw several versions of this cake on this site, but none are the same. I have no idea where this recipe came from but I've had it for at least 30 years, maybe longer.

• Ready In: 1 hr
• Yields: 1 cake

Ingredients

• 2  cups flour
• 1  cup sugar
• 1⁄2 cup  cocoa
• 2  teaspoons baking soda
• 1  cup mayonnaise (or salad dressing)
• 1  cup boiling water
• 1  teaspoon vanilla

Directions

1. Sift flour, sugar, cocoa and soda together three times.
2. Mix mayonnaise, boiling water, and vanilla.
3. Beat 2 minutes. Add dry ingredients.
4. Pour into a cake pan.
5. Bake 325 to 350 degrees for 45 minutes.
6. Frost with your favorite creamy chocolate frosting.