In a large stainless steel pan over medium-low heat, add 1 tablespoon of olive oil. Once heated, carefully add 1 pound of lean ground beef and ½ pound of gluten-free Italian sausage. Cook until browned, about 5-7 minutes.

Stir in ½ medium sweet onion (diced) and 3 minced garlic cloves. Cook until the onion is softened, about 3-4 minutes.

Mix in 2 cups of frozen mixed vegetables and stir for about 4 minutes. Add 3 tablespoons of tomato paste, ½ teaspoon of dried thyme, salt and pepper. Pour in 1 cup of gluten-free broth and 1 tablespoon of Worcestershire sauce, then simmer for 30 minutes.

Preheat your oven to 400°F (200°C). Slice 1 russet potato and 1 sweet potato thinly, aiming for consistent 1/8-inch slices.

Drizzle olive oil in a large pie dish. Layer half of the potato slices over the meat mixture. Sprinkle with paprika and ½ cup of grated Gruyere cheese.

Layer the remaining potato slices on top and sprinkle with the remaining Gruyere and ¼ cup of grated Parmesan cheese. Dot with 2 tablespoons of butter.

Cover with foil and bake for 30 minutes. Remove foil and bake for an additional 25-30 minutes, or until potatoes are tender and golden.

Let the pie rest for 10 minutes before serving. Garnish with freshly chopped parsley.