Preheat the oven to 350 °F (175 °C) and line the bottom of a 9” (23 cm) springform pan with parchment paper. Grease just about 1” up the sides. You don’t want to grease where the cheesecake will be - just the brownies. Position the oven rack to the lower-third section of your oven.

In a medium mixing bowl, stir together the flour, cocoa powder, and salt. Set aside.

In a large mixing bowl, stir together the melted butter, sugar, and vanilla extract. Once combined, add the eggs one at a time and stir just until combined.

Add the dry mixture to the wet and stir just until almost no streaks of flour remain. Do not overmix!

Pour into the prepared springform pan and bake for 15-20 minutes. You’re going to fully bake them and not just do a partial bake. So, a toothpick inserted into the center will come out wet. A toothpick inserted into the sides will come out with some moist crumbs on it, but not totally raw batter. The brownies will continue to bake as they sit in the pan. The top surface should not appear wet.

Let cool for 20 minutes before topping with the cheesecake filling. While it’s cooling, prepare the filling and turn the heat down to 325 °F (167 °C).

In a large mixing bowl using an electric hand mixer, beat together the cream cheese and sugar until well combined.

Add the vanilla, salt and sour cream and beat on low until combined.

Add in the eggs, one by one, until combined. Be sure not to overmix.

Do this once your cheesecake crust has cooled enough for you to handle the pan (after about 15 minutes of cooling). Using heavy-duty, extra-wide foil, cut three pieces that are at least 14" (35 cm) long for your 9" springform pan.

Place the foil pieces on top of each other on a flat surface and put the cheesecake pan in the center of the foil pieces.

Fold the foil up and around the outer edge, but it shouldn’t be attached to the upper rim of the pan.

Get out a roasting pan large enough for your foiled-wrapped cheesecake pan.

Bring a kettle of water to a boil. How much you'll need depends on the size of your roasting pan. It's better to boil too much than to boil too little, and then have to boil more. Should you not have a kettle, then bring water to a boil and then pour it into something shatter-resistant that has a spout, which allows for easy pouring and will prevent water from splashing into the cheesecake. If you think you’ll need 2 kettles of water, then boil 1, pour the boiling water into something shatter-resistant, and boil another kettle. Then, when the 2nd kettle is ready, you’re ready to pour all the water in the roasting pan and don’t have to open the oven door twice.

Place the foil-covered pan into the empty roasting pan. Pour the cheesecake batter over the top of the pre-baked brownie base. Use a silicone spatula to smooth out the top.

Right as the water starts boiling, move the waterless roasting pan with the cheesecake in it onto the oven rack.

Very, very carefully pour the just boiled water into the roasting pan, pouring only about halfway up the sides of the cheesecake pan. Be careful that it doesn't splash onto the cheesecake batter.

Bake at 325 °F (167 °C) for 35 minutes. When you tap the pan, it won't be totally set but won't be super jiggly.

Tilt open the oven door and let cool for 1 hour.

Remove the roasting pan from the oven and carefully remove the cheesecake to a cooling rack.

Cool for 2 hours on a cooling rack or until room temp before chilling for 4+ hours. I let the cheesecake chill for 4 hours and then cover it to prevent condensation from building up and dropping back down onto it. Cover and keep refrigerated for up to 4 days. It can also be frozen for up to 3 months.

Place the chocolate in a small bowl.

Heat the cream in a small saucepan over medium heat until hot and steamy.

Pour the cream over the chocolate and stir until the chocolate is totally melted.

Let sit for about 20-30 minutes or until firm enough to put in a piping bag.

Pipe the ganache over individual slices.