Begin by peeling and cubing your butternut or Kent pumpkin and large potatoes. In a large pot, bring salted water to a boil and add the pumpkin and potato cubes. Cook for approximately 15-20 minutes, or until both are fork-tender. Drain and return to the pot, then mash with reduced-fat butter, seasoning with salt and pepper to taste.

In a large skillet, heat a drizzle of olive oil over medium heat. Once shimmering, add finely chopped brown onion, diced carrots, and red capsicum. Sauté the vegetables for about 5-7 minutes, or until they soften and begin to caramelize. Stir in minced garlic and continue cooking for an additional minute.

Add the extra lean ground beef to the vegetable mixture in the skillet. Use a wooden spoon to break the meat apart as it cooks. Brown the beef for approximately 8-10 minutes, or until it's no longer pink.

Once the beef is browned, incorporate chopped medium ripe tomatoes, stirring to combine. Cover the skillet and let the mixture simmer for about 5 minutes. Then, add in frozen peas, vegetable stock, and gravy powder, mixing well.

Preheat your oven to 400°F (200°C). In a baking dish, spread half of the creamy pumpkin and potato mash across the bottom. Pour your savory beef mixture evenly over the mash, then gently top with the remaining pumpkin mash. Sprinkle a generous layer of grated parmesan cheese across the top.

Place the assembled Pumpkin Shepherd's Pie in your preheated oven and bake for 20-25 minutes until the top is golden brown.