The cake will be baked in a hot water bath, so fill a deep tray with 1” of hot water. Place the tray onto the bottom shelf of the oven while it's preheating.

Wrap the outside of an 8″ round cake tin with foil to make it waterproof if it's not a single mold. Butter and line the base of the tin.

Beat the egg whites and the tartar in a stand mixer until it begins to foam, then gradually add in the sugar and continue whisking until it reaches soft peaks.

Meanwhile, in a large microwave safe bowl, gently melt together the cream cheese, butter and milk in short 10 second bursts. (You can melt it in a small pot on the stove, but don't boil).

Whisk the mixture together to emulsify, then add in the yolks, lemon, flour and cornstarch. Whisk to combine.

Using a spatula, fold a third of the egg whites through the batter, being careful not to deflate the mixture. Repeat until all the egg whites have been folded in.

Pour mixture into the tin and loosely cover the top with foil. Carefully place the cake tin into the hot water bath and bake for 1hr. For the last 10 minutes, remove the top foil so the top can turn golden brown.

Turn off the oven and slightly crack the door open, leaving the cake inside to cool for 1hr.