Begin by greasing an 8″ or 9″ square cake pan and preheating the oven to 350F. Chop the chocolate and set it aside in a bowl.

In a small mixing bowl, combine the yogurt, oil, eggs, and vanilla until thoroughly combined.

In a separate large mixing bowl stir together the sugar, flour, baking powder, and salt until well mixed. Toss a couple of tablespoons of the flour mixture over the chocolate– this helps it disperse through the dough and not sink.

Create a well in the center of the dry ingredients and pour the wet ingredient mixture into it. Stir them together until the mixture is just combined into a thick batter–do not overmix. Add in the chopped chocolate and stir it into the batter. Pour it into the prepared cake pan and bake for 40-45 minutes, or until a toothpick inserted in the center comes out clean or with only a few moist crumbs. Make sure you’re poking into the crumb, and not just a chunk of chocolate since that will always look messy.

When the cake is done, remove it from the oven and allow to cool. Cut into squares and store in an airtight container for 4-5 days. The cake can also be frozen.