Peel and cube the potatoes into even pieces. Boil in salted water for 15–20 minutes, or until fork-tender. Drain well and let cool slightly before mashing.

In a large bowl, mash the potatoes with butter until smooth and creamy. Stir in chopped fresh dill, salt, smoked paprika, a pinch of black pepper, and a sprinkle of oregano. Taste and adjust seasoning if needed. Set aside while preparing the beef.

In a skillet over medium heat, cook the ground beef until browned and cooked through. Add diced onion and minced garlic. Sauté for 2–3 minutes until softened. Stir in chopped red bell pepper, diced tomato, and tomato paste. Cook for 5–7 minutes, stirring occasionally, until everything is softened and fragrant. Remove from heat and stir in chopped parsley.

Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper. Using a spoon or hands, shape the mashed potatoes into rounds (like small pancakes or thick patties). Press the center down gently to form a 'nest' indentation for the beef. Place each nest on the prepared baking sheet.

Spoon the beef mixture into the center of each potato nest. Top generously with mozzarella cheese.

Bake for 15 minutes, or until the edges are lightly golden and the cheese is bubbly and golden. Optional: Turn on the broiler for the last 2–3 minutes for an extra crisp top.

Let the nests rest for 5 minutes before serving—they’ll be hot inside! Serve warm as a handheld appetizer, side dish, or main course.