Step 1

Place a rack in lower third of oven; preheat to 350°. Brush an 8"- or 9"-diameter cake pan evenly with butter. Line bottom with a parchment paper round, then line sides with a 4" parchment collar (this cake will rise up the sides, so yeah, it needs to be 4" high), making sure the ends overlap by at least 3". (Take your time to smooth out the parchment because every wrinkle will show up in the final cheesecake. Or crumple the parchment fully before lining the pan and go for an intentionally wrinkled cheesecake.) Place a wire rack in a roasting pan or scrunch up foil to make a ring for the cheesecake to rest on since you want a layer of water between the roasting pan and cake pan. Bring a large pot of water to a boil.

Step 2

Separate yolk from 1 egg over a small bowl to catch egg whites. Place egg yolk in another small bowl; set egg white aside for making pound cake. Beat cream cheese, sugar, and salt in the bowl of a stand mixer fitted with the paddle attachment on medium-high speed, scraping down sides of bowl halfway through, about 3 minutes. Mix in sour cream until combined. Add remaining 3 eggs one at a time, scraping down bowl after each addition, then add egg yolk and vanilla and mix just to incorporate. Scrape batter into prepared pan; reserve bowl for making pound cake. Tap cake pan firmly against counter to eliminate any air bubbles in batter. Place into prepared roasting pan and slide onto oven rack. Pour boiling water into roasting pan to come halfway up sides of cake pan. Bake until cheesecake is mostly set and only wobbles slightly in the center, 30–40 minutes.

Step 3

While the cheesecake is baking, beat sugar, butter, baking powder, and salt in reserved bowl (no need to wash it out) with mixer on medium-high speed until pale and very fluffy, 6–8 minutes. (You might think it’s done before that time, but keep going all the way). Scrape down sides of bowl, and beat in egg, then reserved egg white, scraping down bowl after each addition, until incorporated.

Step 4

Five minutes before cheesecake is done baking, add sour cream and vanilla to pound cake batter and beat just to combine. Add flour and mix with a rubber spatula just to combine.

Step 5

Remove cheesecake from oven and gently dollop pound cake batter all over top of cheesecake with a spoon. Use spoon to delicately smooth surface, taking care not to push into cheesecake. Bake until cake is deep golden brown (it should be very dark) and bounces back when gently pressed in the center, 35–40 minutes. (This cake is very moist, so it’s better to overbake rather than underbake it.) Remove cake pan from water bath and let cheesecake cool 30 minutes (just so it’s not piping hot). Transfer to the fridge and chill at least 3 hours.

Step 6

For the best texture, let cheesecake sit at room temperature 30 minutes before serving. Run an offset spatula or butter knife along inside of pan to loosen cake. Place a large plate upside down over cake and flip pan and plate over to turn cake out onto plate. Peel away parchment and dust top of cheesecake with powder of choice if desired. For clean slices, cut with a knife dipped in hot water, wiping blade clean between each cut. Serve with fruit if desired.

Step 7

Do ahead: Cheesecake can be made 5 days ahead. Tightly wrap and chill, or freeze up to 1 month.