1. preheat the oven to 350f/175c and grease and line a 9" round springform pan. 2. Whisk together the flour, baking powder, and salt in a medium bowl and set aside. 3. In a large mixing bowl, whisk together the butter and sugar. then add the egg, vanilla, lemon zest, and lemon juice and mix to combine. 4. Add the dry ingredients and mix until smooth. 5. Spread the thick batter in an even layer in the bottom of the springform pan. set aside. 6. In a large mixing bowl using a hand or stand mixer with the whisk attachment, mix the cream cheese until smooth. 7. Mix in the powdered sugar, one cup at a time, until thin and creamy. 8. Then mix in the egg and lemon zest. 9. Pour the cream on top of the lemon batter, pouring right in the middle and allowing it to naturally spread close to the edges. it may need some help fully spreading, so use a spoon to nudge it out close to the sides. 10. Bake for 35-40 minutes, or until the top has formed a golden skin and it's evenly puffed. 11. Allow the cake to cool at room temperature for about 30 minutes, then transfer to the refrigerator and chill uncovered for about 2 hours. this is important as it allows the cream to set. 12. Run a knife around the edge of the pan and release the cake. top with a dusting of powdered sugar then slice and enjoy!