Crack the eggs into a mixing bowl and fish out the yolks.
Sprinkle a little cream of tartar into the whites and beat them until you have peaks.
Dump in the powdered sugar and beat for about five minutes until you get your peaks back.
Put the chocolate chips in a microwave-safe bowl, and put the butter on top in a few chunks.
Microwave until the chocolate is just hot enough to melt when mixed.
Beat the chocolate and butter together until melted, heating it up some more if necessary.
Into the melted chocolate mixture, add the cocoa powder, a glug of vanilla, pinch of salt, any additional chocolate chips you want for chunks, the yolks if you're using them, and just enough of the meringue to make sure the mixture stays liquid while you beat it smooth.
Scrape into the bowl with the meringue and beat until the two just barely come together.
Lay parchment paper on a sheet pan and then spray the paper with cooking spray.
Deposit the batter in six big lumps using an ice cream scoop, if you have one.
Bake at 350ºF/180ºC until the surfaces crack and the outer edges start to brown.
Let cool thoroughly before peeling them off the paper.
