Preheat the oven to 450F. Grease & line a 7" springform w/ parchment paper, so it comes at least 2" above the top of the pan around the full circumference.

Brownie base: In a small bowl, combine the chocolate & butter. Heat in the microwave at 20sec intervals, until melted & smooth. Add the egg & sugar; whisk to combine. Sift in the flour & salt; gently fold until just combined. Spread batter evenly into the base of the prepared pan. Set aside.

Cheesecake Filling: In a small bowl, melt the dark chocolate in the microwave at 20sec intervals, until smooth. Set aside to cool.

In a large bowl, beat the cream cheese. Add the sugar; beat until combined. Add the cocoa powder & espresso granules; beat until smooth.

Now, I like to whisk by hand to ensure I'm not over-mixing! Whisk in the eggs, one at a time, until combined. Add the melted chocolate & whisk. Then, add the heavy cream & whisk until smooth.

Pour the filling into the pan on top of the brownie batter. Gently tap the pan to eliminate any air pockets.

Bake at 450F for 25-30 mins, or until the top is dark brown & the center is still slightly jiggly.

Crack oven door & let sit for 5 mins. Then, remove & place directly into the fridge to chill for at least 4 hrs or overnight.

Prepare Ganache & Serve: Place chocolate into a bowl. Heat the heavy cream in the microwave until hot (~1 min); pour it over the chocolate & let sit for 5 mins. Whisk until smooth & glossy.

Pour the ganache over cheesecake. Garnish w/ flaky sea salt.

Slice & enjoy!