Preheat the oven to 375°F and prepare 2 aluminum baking sheets lined with parchment paper; set aside.

In the bowl of an electric stand mixer, cream together the butter and sugars until creamy. Add the vanilla and eggs and mix until combined.

In a separate mixing bowl, whisk together the flour, baking soda, baking powder, and salt. Add to the wet ingredients while mixing on low, adding a little at a time, until all the ingredients are combined into a dough; do not overmix.

Add the chocolate chips and dark chocolate pieces to the dough and disperse evenly with your hands or a wooden spatula.

Pinch off large golf ball-sized pieces of dough and roll them between your hands before arranging them on the cookie sheets. Evenly space the cookies, 5-6 per sheet, and bake for 12-15 minutes or until the edges just start to brown.

Let cool before transferring to a cookie rack. Repeat for the rest of the cookie dough. Let the cookie sheets cool completely before reloading.

Once the cookies are completely cooled, you can add the marshmallow spiderwebs. Microwave a handful of marshmallows for about 15-20 seconds or until inflated and very warm. Pinch off some of the melty marshmallow with your hands and pull apart with your fingers until a stringy web forms. Lay over a cookie and pinch off at the sides. I use a second person's help with this part to hold the cookie higher than the work surface so that I'm not pinching off the sticky marshmallow over the tabletop.

If you want to get really creative, try making 3D edible spiders with black cocoa powder royal icing! (Recipe within this blog post)