Preheat oven to 400 degrees. Brush 8 cups of a standard muffin tin with butter and dust with sugar tap out excess. Melt chocolate in a heatproof bowl set over (not in) a pan of simmering water, stirring until smooth. Let cool.

In a bowl, whisk together flour, espresso powder, and salt. With a mixer on medium-high speed, beat butter with sugar until light and fluffy. Add eggs, one at t time, mixing until completely incorporated. Add flour mixture beat until combined. Beat in vanilla and chocolate.

Spoon batter into prepared cups. Bake until cakes no longer jiggle when tin is shaken, 8-10 minutes. The cakes will collapse in the center. Let cool on a wire rack 10 minutes before turning out cakes. Spoon ganache into the center and sprinkle with chopped pistachios.

*For the glaze, place 1 cup chocolate chips in a bowl. Heat 3/4 cup heavy cream just until it scalds and pour over the chocolate chips. Allow to sit for just a few minutes then whisk until smooth and uniform.