Preheat your oven to 350°F (175°C) and prepare a baking dish by greasing it.
In a microwave-safe bowl, melt the dark chocolate chips and butter or coconut oil together until smooth.
Allow the melted chocolate mixture to cool slightly before adding the eggs, maple syrup or honey, Greek yogurt, and vanilla extract. Mix until well combined.
In a separate bowl, whisk together the cocoa powder, baking soda, and salt.
Gradually incorporate the dry ingredients into the wet mixture, stirring until just combined.
Pour the batter into the prepared baking dish and smooth the top.
If desired, sprinkle extra chocolate chips on top of the batter.
Bake in the preheated oven for about 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Let the cake cool before slicing and serving.
