Creamy Seafood Pot Pie

Preheat oven to 400 degrees F.

Melt butter over medium-heat in a large Dutch oven. Saute potato, leeks, and celery for 10 minutes. Add thyme and garlic; cool 1 minute. Sprinkle flour over vegetables, and cook, stirring constantly, 3 minutes. Whisk in milk; bring to a boil. Reduce heat to low, and simmer 2 to 3 minutes or until potato is almost tender.

Add cod and and next 3 ingredients; return mixture to a simmer. Remove from heat. (Fish will be under cooked.) Ladle filling into individual oven-proofed soup crocks.

Roll out pastry on a lightly floured surface until smooth. Cut pastry on a lightly floured surface until smooth. Cut pastry into circles, cutting the circles 1 inch larger than the mouth of the soup crocks. Whisk together egg yolk and 1 tablespoon water; brush the underside of the pastry edges with egg wash and place over crock, pressing edges to seal. Brush top with egg wash. Place crocks on baking sheet. Bake at 400 degrees F for 14-16 minutes or until pastry is golden brown.