Set the oven to 350°F (175°C). Generously butter either 6 to 8 ramekins or a 9-inch cake pan. For added assurance that the cake won’t stick, lightly dust with flour or place parchment paper on the bottom.

In a large bowl, combine softened butter and cream cheese. Beat until the mixture is light and creamy, about 2–3 minutes on medium speed. Add the granulated sugar and continue beating for another 2 minutes until the mixture becomes fluffy.

Add the eggs one at a time, beating well after each one. Stir in the vanilla extract and salt, making sure everything is well incorporated.

Gradually add the flour and mix just until everything is combined. Avoid overmixing — the batter should be smooth but not overworked.

Spoon the batter evenly into the buttered ramekins or pour it into the prepared cake pan. Leave some space at the top to allow room for the cream cheese topping.

In a separate bowl, beat together the softened cream cheese, sugar, egg, and vanilla until smooth. Spoon a thin layer of this topping over the batter in each ramekin or spread it over the large cake.

Place in the preheated oven and bake for 50–55 minutes. The top should be golden, and a toothpick inserted into the center should come out clean, aside from a bit of the cream cheese topping. Let the cake cool in the pan for about 10 minutes before serving. It’s best enjoyed warm, with a scoop of vanilla ice cream or a handful of fresh berries.