Place potatoes into a large pot and cover with salted water. Bring to a boil, then reduce heat to medium-low, cover, and simmer until tender, about 20 minutes. Drain and allow to steam dry for a minute or two, then mash with salt, pepper, 2 tablespoons butter, and half-and-half; set aside.

Preheat oven to 400 degrees F (200 degrees C).

Meanwhile, stir together the elk meat, Italian seasoning, salt, and pepper in a skillet over medium-high heat until crumbly and no longer pink, about 5 minutes. Spread the cooked elk meat into a 9-inch pie plate or baking dish and return the skillet to the stove over medium heat.

Place the onion, parsnip, and garlic powder in the skillet, season to taste with salt and pepper, and cook until the turnip has softened, about 10 minutes. Stir in the mixed vegetables and cook an additional 5 minutes, then spread in the pie plate over the elk. Finally, spread the mashed potatoes evenly over the top, and brush the melted butter on the potatoes.

Bake in preheated oven until the potatoes begin to turn golden brown, about 30 minutes. Serve hot.