Cook the pasta (Spirali) al dente, about 10 minutes. Drain and set aside.
Cook the minced beef (750 g) in a large skillet over medium-high heat for about 7 minutes, stirring frequently, until browned. Season with salt and pepper.
Dice the onion into cubes and cut the sheep cheese into cubes.
In a baking dish, combine the cooked pasta, browned beef, diced onion, and diced sheep cheese. Mix well.
In a bowl, whisk together the tomato paste (2 tablespoons), sour cream (1 cup), and cream (1 cup). Mince or press the 3 garlic cloves and stir into the sauce. Season with salt, pepper, and chilli powder.
Pour the sauce over the casserole mixture and stir gently to combine.
Sprinkle the grated cheese (150 g) over the top.
Bake in a preheated oven at 180°C (350°F) for about 30 minutes, until the cheese is melted and golden.