Peel and quarter potatoes for uniform size.

Boil potatoes until fork tender and drain.

Add 1 Cup butter to drained potatoes and mash, seasoning with salt and pepper to taste.

When potatoes are boiling, add 1 Tbsp cooking oil to large sauté pan and heat over medium heat.

Add 1.5 Cup chopped onion once heated, cook for 4-6 minutes or until fragrant, then add garlic cooking another minute.

Add ground beef and break up with a wooden spoon. Once broken up, season with 1 Tbsp Prime Rib Seasoning and cook until no pink shows.

Add 2 Tbsp tomato paste, 1 Cup beef broth, 4-6 Tbsp flour, 1 Tbsp Prime Rib Seasoning, and 2 tsp Worcestershire stirring well to combine.

Bring mixture to a boil, cover, and reduce heat to low for a slow simmer for 10-12 minutes.

Add frozen veggies to mixture, stir well, and pour into a deep baking dish in an even, single layer.

Cover mixture with mashed potatoes, taking care to seal edges so meat filling doesn't boil through.

Bake for 20-25 minutes at 400°F or until tops of potatoes begin to brown.