01 In a medium saucepan over medium-low heat, melt the butter. Remove from heat. Whisk in the sugar, lemon zest, and lemon juice. Add the egg and whisk until smooth.
02 Return the saucepan to medium low heat and cook, whisking constantly, until sauce thickens and coats the back of a spoon, approximately 5 minutes. (Note: Do not boil or the eggs will scramble.) Remove from heat. Whisk in the cream; set aside to cool.
03 In a medium mixing bowl, using an electric mixer on medium-high speed, beat the cream cheese and yogurt until combined.
04 To serve, spread about 2-1/2 tablespoons of the filling onto one half of each crepe. Fold crepe in half over the filling, then fold almost in half again. Place two filled crepes on each serving plate.
05 Top each serving with a generous tablespoon of lemon sauce and some fresh berries. Serve immediately.