1. Prepare crust topping. In a large bowl, using an electric mixer on low speed, beat 1/2 cup butter and cream cheese until smoothly blended, about 45 seconds. Sift 1 cup flour and salt on top of cream cheese mixture and sprinkle in 3/4 tsp. black pepper. Mix until dough holds together and forms large clumps that come away from sides of bowl, about 30 seconds. Form dough into a smooth ball, flatten it into a 6-inch disk, wrap it in plastic wrap, and refrigerate for 45 minutes to 1 hour, until dough is firm enough to roll out without sticking.
2. While dough chills, prepare sauce and filling. Preheat oven to 375 degrees F. Have ready a 9-by-2-inch round baking dish or glass pie plate.
3. For sauce, melt 2 tbsp. butter over low heat in a large saucepan. As soon as butter melts, add 2 tbsp. flour and increase heat to medium. Using a wooden spoon and stirring constantly, cook butter and flour until mixture is bubbling and just beginning to turn golden, about 1 minute. Whisking constantly, slowly pour in vegetable broth. Keep whisking until sauce is smooth. Bring to a gentle boil, adjusting heat as necessary, and cook for 5 minutes. Sauce will begin to thicken slightly, to the consistency of a thick syrup. Set aside.
4. For filling, in a large skillet, heat remaining butter over medium heat until it begins to bubble gently. Add onion and garlic and cook, stirring often, until onion softens, about 5 minutes. Add onion mixture to sauce and stir in carrots, parsnips, potatoes, celery root, and leeks. Return saucepan to medium heat and cook, stirring often, for about 10 minutes, adjusting heat to keep liquid at a gentle boil, until carrots, parsnips, potatoes, and celery root are slightly softened. Stir in parsley and thyme. Remove saucepan from heat and add salt and pepper. Transfer filling to baking dish and let it cool for 15 minutes.
5. Lightly flour rolling surface and rolling pin. Roll dough to a shape that's 1 inch larger around than top of baking dish. Roll up pie crust onto rolling pin and unroll it over top of baking dish. Fold 1/2 inch of the edge of the crust under itself to form a smooth edge. Use your thumb and forefinger to pinch the edge of the crust into a fluted or scallop. Using a pastry brush, brush crust lightly with water, then sprinkle lightly with salt and pepper. Cut four 2-inch-long slits in top of crust to release steam while potpie bakes.
6. Bake about 35 minutes until crust is lightly browned. Let rest for 5 minutes, then use a large spoon to cut down through crust and scoop out servings of crust and filling.
Source: Hannaford fresh Magazine, November - December 2007