Separate egg yolks from egg whites and set yolks aside. Measure out dry ingredients and set aside. Measure butter and coconut oil and set aside.
Beat egg yolks until pale in color, then add erythritol and stevia. Beat again until well combined.
Add heavy cream, lemon juice, lemon zest, coconut oil and butter. Beat again until fully combined.
Sift dry ingredients over wet ingredients and mix well again.
Distribute batter between 2 ramekins, then push 2 tbsp. Blackberries into each ramekin. You want to slightly crush the blackberries with your finger before pushing them into the batter.