Preheat the oven to 400F. Line a 12-cup muffin pan with muffin liners and set aside.
In a medium bowl, whisk together 2 cups flour, 1/2 cup cocoa powder, 2 teaspoons baking powder, salt, and spices.
In a separate large bowl, whisk together the eggs and 3/4 cup sugar until lightened and thick. Add 1 cup Greek yogurt, 1/2 cup oil, 1/2 cup milk and 1 teaspoon vanilla, and whisk until combined.
Add the dry ingredients to the wet ingredients in three additions and fold in until just combined - do not overmix.
Fold in the chocolate chips. The mixture will be very thick. Some lumps are okay.
Divide the batter evenly between the muffin cups, and bake for 15 - 20 minutes, or until a toothpick inserted into the centre comes out clean.
Allow to cool for 5 - 10 minutes in the pan before adding the powdered sugar.