Shrimp Newburg Tartlets

3 dozen tiny frozen tartlet shells
2 tins (12 oz) cocktail shrimp, drained
4 Tbsp butter or margarine
1 Tbsp flour
1/2 tsp salt
1/4 tsp pepper
dash ground nutmeg
1 cup light cream
1 egg yolk
2 Tbsp dry sherry

Prick the bottom of the tartlets shells and bake according to package directions. Cool completely. Set aside 36 small shrimp for garnish. Place remainder of shrimp in tartlet shells. Set shells in a large shallow baking pan. Melt butter in a small saucepan. Stir in flour, salt pepper, and nutmeg. Cook, stirring constantly until bubbly. Stir in cream and continue cooking until the sauce thickens and boils for 1 minute. Beat egg yolk in a small bowl. Beat in about half of the hot sauce, then stir the egg-yolk mixture back into remaining sauce in the pan. Cook, stirring constantly, for 1 minute. Stir in sherry. Spoon over shrimps in shells. Bake in 300 oven for 15 minutes, or until hot. Garnish with reserved shrimps. Serve hot.