Add the sweet potatoes to a pot of salted, cold water.
Place the pot on the stovetop and bring the water to a boil.
Cook the sweet potatoes until they are tender, about 20 minutes.
Drain the sweet potatoes and cool until they are cool enough to handle.
Remove and discard the sweet potato skins.
In a large bowl, add the sweet potato flesh, the butter, 1/4 cup of the grated parmesan cheese, 1 teaspoon of the salt, and 1/2 teaspoon of the pepper, and mash to combine. Set the mashed sweet potatoes aside.
Preheat the oven to 400 degrees F.
Lightly coat six to eight individual casserole dishes with nonstick spray.
In a large skillet over medium-high, add the ground pork and cook, while crumbling, until it is no longer pink, about 5-8 minutes.
Drain the fat from the skillet.
Transfer the cooked meat to a plate and wipe the skillet clean.
In the same skillet over medium-high heat, add the oil.
Add the onion and the mushrooms to the oil and cook until tender, about 4-5 minutes.
Add the garlic and cook until fragrant, about 1-2 minutes.
Add in the broth, the tomatoes and their juices, the dried rosemary, and the Worcestershire sauce and stir to combine.
Bring the broth mixture to a boil.
Reduce the heat to medium and simmer until thickened.
Add the cooked pork, the corn, and the peas and carrots mix to the broth mixture and stir to combine.
Taste the pork mixture for seasoning, adding the extra salt and the extra pepper as needed, and cook until heated through, about 2 minutes.
Divide the pork mixture evenly among the prepared casserole dishes.
Spread an even amount of the mashed sweet potatoes over the pork mixture in the casserole dishes.
Place the baking dishes on a large baking sheet.
Bake uncovered until the tops are lightly browned, about 15-20 minutes.
Serve garnished with the extra shredded parmesan and the fresh rosemary leaves.