Boil the potatoes: Start by first cooking the potatoes in boiling water for about 15 minutes or until fork tender. While the potatoes are cooking, you can prepare the meat mixture.
Prepare the meat mixture: Heat the oil in a large skillet over medium heat. Add the ground beef to the skillet, season it with the salt and pepper and cook it for abut 5 minutes or until it's no longer pink, breaking it up as you go along.
Add the onion and garlic and cook for 3 more minutes until the onion softens and becomes translucent. Add the pepper flakes, Worcestershire sauce, onion soup mix, beef broth and stir. Stir in the frozen veggies and cook for a couple more minutes. Set aside.
Preheat the oven 350 F degrees.
Prepare the mashed potatoes: Drain the potatoes then add them to a large bowl. Add in the butter and using a potato masher, mash until smooth. Add the milk, Parmesan cheese, salt pepper and mash a bit a more until smooth.
Finish assembling the shepherd's pie: Spread the potatoes over the meat and smooth with a spoon. Take a fork and rough up the top a bit and garnish with a bit of parsley.
Bake: Place the skillet on a baking sheet, then place it in the oven and bake for 40 minutes until golden brown on top.
Garnish with more parsley and pepper and serve warm.
How do I store leftovers: Refrigerate leftovers within 2 hours of cooking, cover the pie with plastic wrap and refrigerate for up to 3 days.
Can I freeze this: Yes you can! After baking, let the skillet cool to room temperature. Transfer the shepherd's pie to an airtight container and place in the freezer for up to 2 months. You can also cover the skillet tightly with foil, or plastic wrap, just make sure it's tightly covered.
Can I use store bought mashed potatoes: Yes, you can. Store bought mashed potatoes can be used or leftover mashed potatoes.
Can I use fresh veggies: Yes, of course. I used frozen veggies to save time, but feel free to use fresh veggies, such as carrots, peas and corn.
I don't have onion soup mix, what can I use instead: You can make your own onion soup mix by combining: 3 tbsp minced onion flakes, 2 tbsp beef bouillon powder, 1/2 tsp onion powder, 1/4 tsp parsley flakes, 1/8 tsp ground celery seeds, 1/2 tsp sweet paprika, salt and pepper to taste.
Please keep in mind that nutritional information is a rough estimate and can vary greatly based on products used.