• Preheat an oven to 425 degrees F.

Make the Filling

• Place the peas and carrots, green beans, and celery into a saucepan; cover with water, bring to a boil, and simmer over medium-low heat until the celery and potatoes are tender, about 10 minutes. Drain the vegetables in a colander set in the sink, and set aside.
• Melt the butter in a saucepan over medium heat, and cook the onion and leeks until translucent, about 5 minutes. Stir in 2/3 cup of flour, salt, black pepper, celery seed, onion powder, and Italian seasoning; slowly whisk in the chicken broth and milk until the mixture comes to a simmer and thickens. Remove from heat; stir the cooked vegetables and chicken or turkey meat into the filling until well combined.

For 2 Pies

• To bake 2 pies, fit 2 pie crusts into the bottom of 2 9-inch pie dishes.
• Spoon half the filling into each pie crust, then top each pie with another crust. Pinch and roll the top and bottom crusts together at the edge of each pie to seal, and cut several small slits into the top of the pies with a sharp knife to release steam. Brush with cream or milk if desired.

For 1 Pie

• Transfer half of the filling to a pie dough lined pie plate. Add the top crust, pinch edges, and cut slits in the top. Brush with cream or milk if desired.
• Let the remaining filling cool, then transfer it to a resealable gallon sized freezer bag, press out the air, seal, and lay flat in freezer to take up minimal space. When ready to use, thaw and warm the filling in a saucepan before pouring into bottom pie crust.

For Individual Pies

• To make individual pies, roll out pie dough for a single crust pie and use an inverted empty ramekin as a cookie cutter to cut out circles of pie dough. Repeat with the second crust.
• Divide the filling evenly between 8 ramekins (or fill 4 ramekins and freeze remaining filling). Place circles of pie dough on top of ramekins and add extra pie dough as edge crust. Cut slits in top of each pie. Brush with cream or milk if desired.

Bake the Pies

• Place a foil ring around the edge crust(s). Bake in the preheated oven until the crusts are golden brown and the filling is bubbly, 30 to 35 minutes. If the crusts are browning too quickly, cover the pies with aluminum foil after about 15 minutes. Cool for 10 minutes before serving.