Heat oven to 350°F. Grease two 9-inch round cake pans, line bottoms with parchment, and grease the parchment. Dust with cocoa powder and tap out excess.

In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt until no cocoa lumps remain.

In a separate bowl, whisk coffee, milk, oil, eggs, and vanilla until combined. The mixture will look slightly curdled; this is normal.

Pour wet ingredients into dry and whisk until just smooth, about 30 seconds. Do not overmix. Divide evenly between prepared pans.

Bake 30-35 minutes until cakes spring back when lightly pressed and a toothpick comes out with a few moist crumbs. Cool in pans 10 minutes, then turn out onto racks to cool completely.

Place chocolate in a heatproof bowl. Heat cream until steaming and small bubbles form at the edges. Pour over chocolate, add espresso powder, and let stand 2 minutes. Stir until glossy and smooth. Cool 15-20 minutes until thick but still pourable.

Place one cake layer on a serving plate. Pour 1 cup ganache on top and spread to the edges. Add second layer and pour remaining ganache over the top, letting it drip down the sides. Use an offset spatula to smooth. Let set at room temperature 30 minutes before slicing.