In a large mixing bowl, beat together contents of chocolate cake mix, Greek yogurt and 1 cup of water, till all incorporated and mouse textured.
Spray cupcake pan with cooking spray and spoon batter evenly into cupcake pans, enough for 18 servings.
Cook for 14-18 minutes until toothpick inserted comes out dry or with a little crumble.
As soon as the cupcake pans are out of the oven, with a smaller cup sprayed with cooking spray on the outside, make indentations with the little cup into each hot cupcake, making a space for a pool of chocolate to fill each indentation.
Warm in the microwave for 10-15 seconds at a time and stirring until melted, coconut oil, chocolate syrup and chocolate chips.
Evenly spoon melted chocolate into each indentation.
Cool in the freezer until ready to eat. Then, carefully remove each cupcake from the pan and place on dessert plate. Warm for about 15-25 seconds and serve warm.