Step 1: Sauté the Savory Filling
In a large skillet, melt the butter over medium-high heat. Add the chopped onion, minced garlic, and fresh parsley, cooking until fragrant, about 2 minutes. Stir in the lean ground beef, breaking it up as it cooks. Sauté for 5-6 minutes until the beef is fully browned and no longer pink. For a healthier touch, carefully drain any excess fat.Step 2: Incorporate Veggies & Seasonings
Mix in the grated potatoes, carrots, Worcestershire sauce, low-sodium dark soy sauce, sea salt, and black pepper. Stir well and cook for another 2-3 minutes to slightly soften the vegetables. Finally, stir in the whole wheat Panko breadcrumbs until everything is combined. Take the skillet off the heat and let the meat filling cool down completely (at least 1 hour, or prepare ahead and chill overnight).Step 3: Assemble Your Festive Pie
Preheat your oven to a cozy 400°F (200°C). Gently place one disc of your whole wheat pie dough into a 9-inch pie pan, pressing it down to form the bottom crust. Spoon the completely cooled meat filling evenly into the dough-lined pan.Step 4: Top & Seal
Carefully drape the second pie dough disc over the filling, creating the top crust. Press the edges of both crusts together firmly, then crimp with your fingers for a beautiful seal. Create 5-6 small slits on the top crust to allow steam to escape while baking.Step 5: Golden Finish
Lightly brush the beaten egg over the top and edges of the pie for a beautiful golden-brown finish. If your oven isn't quite ready, pop the assembled pie into the fridge to keep the dough firm.Step 6: Bake to Perfection
Bake the pie in the preheated oven for 20 minutes, until the crust edges turn a lovely golden. Then, reduce the oven temperature to 350°F (175°C) and continue baking for another 40 minutes, until the entire top crust is golden and flaky.Step 7: Rest & Serve
Remove the pie from the oven and let it cool on a wire rack for at least 1 hour before slicing and serving warm. This rest time is crucial for the pie to set beautifully.