Instructions

1. Preheat the oven to 350 degrees F.
2. In a large skillet over medium-high heat, brown the ground beef until it is almost fully cooked and crumbled. Transfer to a strainer and drain the grease. Let sit while you assemble the rest of the casserole to ensure grease is drained really well
3. In the same skillet, add all of the gravy ingredients, except for the arrowroot dissolved in water. Use a whisk to incorporate the dijon and tomato paste until it’s all mixed in to the liquid. Let it come to a simmer and reduce to about half, about 10 minutes
4. While it’s simmering, assemble the casserole ingredients by slicing the onion and mushrooms. Lightly grease a large casserole dish and add in the hash browns, onions, mushrooms and the beef
5. Next, dissolve the arrowroot in about 2 tbsp of water in a small dish, and then pour the flour water mixture into the gravy. Use the whisk again to combine it with the gravy and thicken, about 1 minute. Once it has thickened evenly, pour the gravy into the casserole dish over the beef and vegetables
6. Mix/stir everything around until the gravy is incorporated with all of the ingredients, and then make sure the casserole is in an even layer in the dish. Place it in the oven and bake for 45 minutes to 1 hour, or until the top of the casserole looks “baked” and there’s no appearance of liquid on top