What is the secret of making a perfect moist chocolate cake cause every time I try it comes out dense

Zucchini!

Thanks guys

What is it you want? Moist is not the same as not dense. As you increase the amount of moisture in your chocolate cake you usually increase the density.

Mayonnaise.

Yes, the recipe would be helpful, but also to know the *type* of chocolate cake would be even more helpful. If it's a torte or a low or no flour type of recipe, density is the goal. Also where you live could be a factor - are you at a high altitude or in a particularly humid part of the world? What kind of chocolate or cocoa could be factor, and as well the fat - is your fat liquid or solid? Please re-post with some answers to our questions because clearly we want you to eat and serve the chocolate cake of your dreams!

Most of the time, it's the recipe.

The perfect moist chocolate cake that I always make is the one on the back of the Hershey's unsweetened cocoa powder box. Here's the recipe,
https://www.hersheys.com/recipes/recipe-details.aspx?id=184&name=HERSHEY%27S-PERFECTLY-CHOCOLATE-Chocolate-Cake

I'm not crazy about the frosting recipe, but the cake...ohhhhh the cake.
Makes a chocolate cake that is moist and lightly sweet without being cloying.

Also it could be that cake asks for butter and sugar to be creamed and either you don't do it well or you don't have an electric mixer and you do it by hand. Beating butter with sugar till light and fluffy, not overbeating batter once flour is added, measuring correctly etc., all contribute to a lighter cake.
But I find that the moistest chocolate cakes have oil instead of butter tend to be more moist and light.

hard to tell unless y ou post your recipe.

yoghurt & oil

Coffee

Hmmmm. It could be the recipe. Check the One Bowl Chocolate Cake in food52. Easy to make and moist.