Take two 6oz ramekins and coat with butter and cocoa powder.
Melt chocolate and butter together. To melt it easier, I cut the butter into smaller cubes. Microwave for 30 seconds stir, then in 15 second intervals until smooth. Should not take more then 50 seconds.
In a bowl of a stand mixer, fixed with the whisk attachment, crack the egg. Whip until foamy, about 1 minute. Add sugar and salt in gradually while still running the mixer. Whip until the mixture is thick and a pale yellow. About 7 minutes.
Pour the egg mixture into the chocolate stir to combine. Sprnkle the flour over the top. Fold to combine until it is all incorporated.
Divide batter between both ramekins. Place them in the middle of a cookie sheet. Bake for 10 mintues at 400*F
The middle should be barely jiggling, and they should have risen to the top of the ramekin.
Let cool for a couple minutes, then invert onto serving plates.
Let them sit until the cakes release. DO NOT rush this process. If you try to move them around before they are ready then the fudgy middle may come out all around the cakes.