Saute garlic, onion and chestnuts in butter.
Add remaining ingredients.
Bring to a boil.
Add 4 tbs.cornstarch mixed with 1/4 c.sherry.
Cook until thick and bubbling.
Cool.
Fill crepes with cold filling.
Put thin layer of sauce in casserole, then crepes, remainder of sauce and sprinkle with Parm-esan, cover and bake 45 minutes at 400 degrees.
Remove cover and put under broiler to brown.
Cheese Sauce: After cheese sauce is cooked, add 2 well beaten egg yolks, 4 ozs. Gruyere cheese, small pieces, 5 tbs. Parmesan cheese, 1 tsp.salt and 1/2 tsp.pepper.
Crepes: Combine ingredients in blender jar.
Blend for about 1 minute, scrape down sides with rubber spatula and blend for another 15 seconds until smooth.
Refrigerate batter for at least one hour.
Crepes: It is not necessary to grease pans having non stick coating, others should be brushed with oil or butter.
Heat pan over medium high heat.
With one hand pour in 2 or 3 tbs.batter.
At same time lift pan.above heating unit with other hand.
Immediately tilt pan in all directions, swirling batter to cover bottom in thin layer.
Return to heating unit and cook over medium heat until bottom is browned.
Turn with plastic spatula, cook a few seconds, stack on plate.
May be made ahead and frozen.
Separate with wax paper.
Use upside down or traditional pan.