Preheat the oven to 350°F (175°C). Grease the baking pan.
In a large bowl, mix flour, cocoa powder, sugar, espresso powder, baking soda, and salt.
In another bowl, whisk together sour cream, oil, eggs, and vanilla.
Slowly add the wet ingredients to the dry ingredients, stirring gently.
Pour in the cooled brewed espresso. Mix until just combined.
Fold in the chocolate chips.
Pour the batter into the prepared pan.
Bake for 45 minutes or until a toothpick comes out clean.
Cool the cake in the pan for 10 minutes before transferring it to a wire rack.