Prepare Pie Crust: Mix 1 1/4 cups flour with 1/2 cup of cold cubed butter. Mix it together well until it is crumbly and the butter is about pea-sized. Slowly pour ice water into the flour mixture and mix with a fork until the mixture forms a ball. Don't overmix. It should be JUST this side of crumbly. Add an extra teaspoon or two of water, slowly, if the dough won't stick together. Wrap dough in plastic wrap and place in the fridge.
Peel potatoes if desired, and then dice into 1/2 inch chunks. Season liberally with salt, pepper, garlic salt, onion powder, and seasoning salt. Place on a large baking sheet, and bake for 15-20 minutes at 350.
While potatoes are roasting, make your pie filling by sauteing onions in 1/3 cup butter for 2-3 minutes, or until translucent and soft. Sprinkle 1/4 cup flour over the butter/onion mixture, and stir well so no lumps form. Cook over low heat for 1-2 minutes.
Add red wine, and beef stock. Stir well and simmer over low heat until thickened.
Add garlic, corn, peas, carrots, beef, thyme, and the bay leaf. Simmer over low heat for 5 minutes. Add potatoes into the mix and gently stir. Remove from heat and carefully spoon mixture into a deep dish pie pan, or a medium sized baking dish that's been sprayed liberally with cooking spray.
Lightly flour one large piece of parchment paper. Place pie dough on top, sprinkle a little flour on top, and then add another sheet of parchment. Roll out the pie dough to the size/shape you need for your baking dish, and gently place on top of filling. Trim edges, and roll the edges under a bit. Place a few vent holes in the top of the pie crust. Lightly brush the top with an egg wash.
Bake at 350 for 40-45 minutes, or until mixture is bubbly, and crust is golden brown. Remove from oven and let cool for 20 minutes before serving.
Notes
Easily substitute different veggies into this mix if you prefer a different mix. You can also use frozen diced potatoes in place of fresh to save some time. Subbing in a ready-made pie crust would also speed this up some. I just happened to not have those things on hand. :)