Microwave butter and milk for 20–30 seconds to melt.
Add cocoa powder, erythritol, and salt, and mix well.
Add eggs and vanilla extract, and mix thoroughly.
Add almond flour and combine gently with a spatula.
Pour the batter into a lined pan, smooth the top, and chill briefly in the refrigerator.
Soften the cream cheese at room temperature until smooth.
Mix in erythritol, eggs, vanilla extract, and lemon juice.
Adjust the consistency with yogurt and milk. (If the mixture is too thin, you can add 5g almond flour.)
Pour the cheesecake mixture over the brownie batter and smooth out any bubbles.
Preheat oven: 200°C for 10 minutes → Bake at 200°C for 15 minutes, then lower to 180°C and bake for an additional 10–12 minutes.