Preheat oven to 400°F.
Melt butter over low heat, blend in flour, and continue cooking and stirring 1 to 2 minutes.
Remove from heat and beat in milk.
Return to heat and stir continuously until mixture boils and thickens.
Transfer to a bowl before beating in egg yolks one at a time.
Stirring thoroughly, blend in 3 tablespoons sugar, lemon juice, and lemon peel.
In another bowl, whip egg whites with 1/8 teaspoon salt until they form soft peaks; continue beating until whites form stiff peaks.
Gently fold in a small amount of whites to lemon mixture; then add remaining whites to the mixture.
Add 1 tablespoon of lemon mixture on dessert crepe and fold the crepes in half and in half again.
Place in shallow, buttered baking dish side by side, and bake ,10 minutes.