1. Melt the butter in a medium saucepan over medium heat.
2. Add in the onion and sauté for 3 minutes or until it begins to get soft and translucent.
3. Add the flour in a little at a time, whisking constantly. It should start to thicken immediately.
4. Slowly pour in the broth, whisking after each addition. Adding it slowly will make a nice, creamy texture.
5. Stir in the brisket or ground beef, mixed vegetables, thyme, ketchup, salt and pepper and simmer on low for 20 minutes. If using frozen vegetables, microwave according to package directions, drain, and simmer for 10 minutes instead.
6. Remove from heat and spoon the mixture into 4-6 individual pans, then top with the cooked mashed potatoes.
7. (Optional: top with shredded cheese and broil 5-10 minutes to create a nice outer crust)
8. Serve and enjoy!

To Freeze:

1. Let the pans come down to room temperature, then cover tightly with foil. Freeze for up to 2 months.

To Reheat:

1. Arrange the pans on a flat baking sheet and reheat, covered, in a 350°F (175°C) oven for 30-35 minutes or until a thermometer inserted in the middle reads 165°F (74°C).