Step 1: Prep the Filling

1. Melt butter in a large skillet or pot over medium heat.
2. Add chopped onion and celery, cooking until softened and slightly translucent (around 5 minutes).
3. Stir in the flour and cook for 1-2 minutes until it starts to turn golden.
4. Gradually whisk in chicken broth until smooth. Bring to a simmer, stirring often, until thickened.
5. Stir in heavy cream, diced ham, frozen peas and carrots, and herbs. Season with salt and pepper to taste. Remove from heat.

Step 2: Assemble the Pies

1. Preheat your oven to 400 degrees Fahrenheit (200 degrees Celsius).
2. Lightly grease your baking dish of choice (individual ramekins or a large pie dish).
3. If using store-bought crust, roll it out slightly on a lightly floured surface. For homemade crust, follow your recipe instructions for rolling and preparation.
4. Gently place a bottom crust into your baking dish. If using ramekins, cut the dough to fit.
5. Fill the pie crust(s) with the warm ham filling.

Step 3: Seal and Bake

1. Position a top crust over the filling. Trim and crimp the edges to seal. Cut slits in the top crust to vent steam.
2. Lightly brush the top crust with beaten egg (this helps achieve a golden-brown finish).
3. Bake for 20-25 minutes, or until the crust is golden brown and the filling is bubbly. If using ramekins, the baking time might be slightly shorter.