Sauté meat, stirring constantly to break up any chunks (you want this mixture very smooth, like sloppy Joes).
Add minced onion (if you are using leftover meatloaf you can skip this part) and carrots and continue cooking for about 3 minutes or until vegetables are softened.
Add peas. Add the tomato paste and stir, then add red wine and stock.
Cook until meat has absorbed most of the liquid. Place in an oven-proof dish.
In a separate bowl, whisk eggs and mashed potatoes. Scoop gently on top of the meat filling, leaving some peaks and dollops.
Grate parmesan cheese on top. Bake for 20 minutes or until golden brown on top.