reheat the oven to 375°F. Lightly grease a 9" round metal cake pan. Cut a piece of parchment to fit the bottom of the pan. Lay it in the pan and then grease the parchment.
To make the cake, put the chocolate chips and butter in a microwave safe bowl and microwave until butter is melted and chocolate chips are starting to melt. Stir until mixture is smooth, heating a bit longer if needed.
Stir in the sugar, salt, espresso powder and vanilla. Mix until smooth.
Mix in the eggs, one at a time, until smooth, then stir in the cocoa powder.
Pour batter into prepared baking pan.
Bake the cake for 20 minutes. It should register about 200F on an instant read thermometer.
Remove from the oven and let is cool for 5 minutes. Loosen the edges with a knife, then invert the cake onto a platter or plate.
Cool completely. (I did this a day ahead)
To make the ganache, combine the chocolate chips and cream in a microwave safe bowl. Microwave until cream is warm and chocolate is melting. Stir until smooth.
Pour ganache over the cooled cake and spread with a knife or spatula, letting some of it drip over the edges.
Let the ganache set.
This cake will keep for a week in the refrigerator. Best served at room temperature.
Recipe by white plate blank slate at https://whiteplateblankslate.com/flourless-chocolate-cake/