You can assemble this a day ahead and bake before serving.
Original recipe serves 8
Ingredients (serves 8)
Prepare the filling by combining the vanilla extract, tablespoon of sugar, cream cheese, cottage cheese and egg yolks in a small bowl. Mix with an electric mixer on medium speed until blended. Drop the filling by the spoonful evenly over the batter in the baking dish. Spread evenly with a knife. It's OK if the filling mixes with the batter.
Pour the remaining batter over the filling. Ensure souffle is at room temperature before baking. Bake for 50 to 60 minutes or until puffed and slightly golden. Serve immediately. Serve with extra sour cream or jam, if desired.