1 tablespoon of butter
1 heaping tablespoon of Nutella
2 rounded and firmly packed tablespoons of dark brown sugar
1/2 teaspoon of unsweetened cocoa powder
1/4 teaspoon of pure vanilla
pinch of kosher salt
1 large egg yolk
1/4 cup of all-purpose flour
Start with a microwave safe mug, a tablespoon of butter and one big heaping tablespoon of Nutella.
Melt the butter and Nutella together in the microwave, about thirty seconds. Add two firmly pressed rounded tablespoons of brown sugar, 1/2 teaspoon of unsweetened cocoa powder, a small pinch of kosher salt and 1/4 teaspoon of pure vanilla extract and stir together well.
Then add the yolk from one large egg, and stir again. Do not use the egg white, it makes the cookie gummy and cake like.
Add 1/4 cup of all-purpose flour and stir together again.
Cook in microwave for about one minutes. Let cool for about a
minute and enjoy!