Preheat your oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.

In a medium saucepan, melt the butter over low heat.

Once melted, remove from heat and stir in the sugar until well combined.

Allow the mixture to cool slightly before adding the eggs, one at a time, mixing well after each addition.

Stir in the vanilla extract.

In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Fold in the chocolate chips.

Pour the batter into the prepared baking pan and spread evenly.

Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Allow the cake to cool in the pan for at least 15 minutes before slicing and serving.