Preheat oven to 350 degrees. Line baking sheets with parchment paper and set aside.
In a medium bowl, whisk together flour, cocoa and salt. Set aside.
In a large mixing bowl, beat together the butter and sugar for 4-5 minutes. Add egg, vanilla, cream and espresso powder, and beat until combined. Add dry ingredients and beat until just combined.
Place bowl in the refrigerator for 10 minutes to allow dough to firm up a bit.
Roll dough into 3/4 inch balls and place 1 inch apart on prepared cookie sheets. Using the rounded end of a wooden spoon to gently make an indentation in the center of each cookie.
Bake for 7-8 minutes until cookie is set. Remove from oven and gently press spoon in again to make indentation. Transfer cookies to wire rack to cool.