Individual Chicken Pot Pie

8 Tablespoons (1 stick) butter
1/2 cup all-purpose flour
4 cups chicken broth
1/2 tsp chopped fresh thyme (I simmer the mixture with 3 sprigs and then remove)
1 bay leaf
1/2 cup chopped yellow onions
1/2 cup chopped celery
1/2 cup peeled and chopped carrots
1/2 cup chopped potatoes
1 cup chopped cooked chicken
1/2 cup cooked fresh/frozen peas
salt and freshly ground pepper to taste
Pepperidge Farm puff pastry squares
1 egg beaten with 1 tsp water

Preheat oven to 400 degrees. In a large saucepan over medium heat, melt butter. Add flour and cook, stirring constantly, until mixture smells fragrant and nutty, 1 to 2 minutes. Slowly add broth, whisking until smooth and bring to a boil. Add thyme, bay leaf, onions, celery, carrots, potatoes, chicken, peas, salt, and pepper and cook until potatoes and carrots are tender. We like to let it simmer about 30-45 minutes. Remove from heat an dlet cool for 5 minutes. Discard the bay leaf and thyme sprigs.
Divide filling among ovenproof bowls and place on a baking sheet. Brush puff pastry squares with egg mixture. Brush rims of bowls with water. Place 1 pastry square on top of each bowl, pressing lightly on edges. Bake until pastry is puffed and golden brown, about 20 minutes. Let rest for 5 minutes before serving.