Separate egg whites from yolks. In a heatproof bowl, combine cream cheese and milk. Microwave in 10–15 second bursts, stirring between, until smooth.
Whisk in the egg yolks, vanilla extract, and lemon juice. Sift in the cake flour and whisk until smooth.
In a clean, dry bowl, beat egg whites until soft peaks form. Gradually add sugar and continue whipping until stiff peaks form.
Gently fold the egg whites into the yolk mixture in 2–3 batches. Keep the batter light and airy.
Butter the rice cooker insert. Pour in the batter and tap the bowl to remove air bubbles. Select the “cake” or standard cook setting and cook for 40–50 minutes or until a skewer comes out clean. You may need to restart the cook cycle once.
After cooking, keep the lid open and let the cake rest in the rice cooker for 10 minutes. Carefully remove and cool completely before slicing.