Line a 9-inch (23cm) springform pan with two large sheets of parchment paper, positioning them in a criss-cross so the paper rises at least 2 inches above the pan rim on all sides. Firmly press the paper into the edges and sides, pleating as needed. This reinforced sling is key for lifting out the soft cheesecake and avoids overflow during baking.
Set your oven rack to the center and heat oven to 425°F (220°C), at least 25 minutes before baking. Use an oven thermometer to guarantee the temperature, as the high heat is critical for rapid browning and proper set. Do not use convection mode for this cheesecake.
In a large mixing bowl, beat the room temperature cream cheese and granulated sugar together on medium speed with an electric mixer until absolutely smooth and creamy, scraping down the bowl and beater at least twice. Target: no visible lumps remain and mixture turns satiny after about 2-3 minutes of beating.
Crack the eggs into a small bowl. Add them to the cream cheese mixture one at a time, mixing well and scraping after each addition. Blend just until the last streak disappears before adding the next. Avoid whipping in excess air; the batter should be lush and glossy, not foamy.
On low speed, pour in heavy cream, vanilla extract, and sprinkle in the kosher salt. Blend until smooth and uniform, stopping to scrape down the bowl and beaters once. The finished batter should be pourable and viscous, not runny or overly thick.
Sift the all-purpose flour directly over the batter, then gently fold it in with a spatula, rotating the bowl to avoid overmixing. Fold only until no dry streaks remain, overmixing here can toughen the final custard.
Pour the batter into the lined pan, smoothing the top with a spatula. Tap pan gently to eliminate air bubbles. Bake at 425°F (220°C) for 26-32 minutes until the surface is deeply caramelized but the very center jiggles like set custard (not soupy). Rotate pan once during baking for even coloring. Do not overbake, the center should wobble.
Transfer pan to a cooling rack. Cool at room temperature until barely warm (about 2 hours); the cake will settle and deflate slightly. Once fully cooled, lift out carefully by grasping the parchment edges and transfer, still in paper, to the fridge. Chill uncovered for at least 4 hours, or overnight for the cleanest slices. Serve at cool room temperature, using a hot wet knife for neat cuts.