Preheat the oven to 375º F. Scrub and pierce potatoes; rub with oil. Bake until tender, about 1 hour.

Meanwhile, Make the filling:

In a skillet over medium-high heat, heat the oil, and add the onions. Cook for about two minutes, then add the ground meat.

Season with parsley, thyme, salt, and pepper, and add the rosemary sprigs. Cook the meat, breaking it up with a firm spatula as it cooks.

Once browned, add the garlic and Worcestershire Sauce. Stir and cook for about one minute.

Stir in the tomato paste and sprinkle the flour. Stir and cook for about one minute.

Add the frozen veggies. Mix in veggies and cook for about 3-5 minutes longer. 

Taste filling and adjust seasoning if needed. Set the filling aside.

When potatoes are cool enough to handle, cut a thin slice off the top of each and discard the tops. Scoop out the pulp, leaving thin shells.

In a large bowl, mash the pulp with butter. Add the sour cream, and cheeses. Mash potatoes until combined. Spoon meat mixture into each potato shell; top with potato mixture. 

Place on a baking sheet.

Bake at 375° for 20 minutes. Sprinkle with cheese and paprika; bake until melted, about 5 minutes longer. Sprinkle with chives.