Lemon Sauce (Uses first 6 ingredients)
Melt butter in a medium sauce pan over medium-low heat. Remove from the heat and whisk in sugar, lemon zest and lemon juice. Add the egg and, and mix until smooth. Return saucepan to medium-low heat and cook, whisking constantly, until the sauce thickens and coats the back of a spoon, about 5 minutes. (Do not boil or the eggs will scramble.) Remove from heat. Whisk in the cream and set aside to cool.
Crepes: (Next 8 ingredients)
Prepare crepes by melting 2-tablespoons butter in a small sauce pan over medium heat until lightly brown. Immediately remove from heat. Skim off solids; set aside.
Combine 2-eggs, milk, and water in a blender and blend on medium speed until smooth. Add flour, cornstarch, and salt. Add browned butter and vanilla extract. Blend until smooth. Refrigerate the batter for 30 minutes.
Melt a pat of butter in a 6-inch nonstick skillet over medium heat. Pour a scant ¼-cup batter into skillet, tilting skillet so the batter covers the bottom in a thin layer. Cook until crepe is lightly browned, about 1 ½ minutes. Loosen a corner of the crepe, turn over, and cook until very lightly browned, another 15 seconds. Transfer to a plate. Continue cooking crepes, stacking until there are at least 12, adding more butter to the pan as necessary. Cool to room temperature.
Filling (Last 3 ingredients)
Beat the cream cheese and yogurt in a medium mixing bowl with an electric mixer on medium-high speed until combined.
Spread about 2 ½-tablespoons of the filling on 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.