Preheat the oven to 350 degrees F. and prepare two 5 inch skillets by wiping them with a little bit of butter.
Use an electric mixer to cream the butter and sugars together until light and fluffy, about 3 to 4 minutes.
Mix in the egg white and vanilla extract.
Add the flour, cocoa and baking soda and continue to mix until combined.
Stir in the chocolate chips and chopped Snickers. The dough will be thick.
Divide the cookie dough between the two skillets and press evenly into skillets.
Bake for 20 to 25 minutes. The edges should look done. The center might look a little undercooked, but that's ok. It'll cook a little more as it cools.
Allow the cookie to cool for about 10 to 15 minutes, then add a scoop of ice cream and serve.
Notes
This rich dessert could easily be divided into 6 servings rather than 4.