Melt clarified butter in a roaster over medium-high heat.
Add minced beef, breaking it into small pieces, and fry until brown (roughly 5-7 minutes).
Add leek rings and sauté for 2 minutes.
Add tomatoes and tomato paste, stir constantly, and bring to a boil.
Season with salt, pepper, and paprika to taste.
Reduce heat to low and simmer for 15 minutes.
While the meat simmers, cook the spaghetti in salted water according to the packet instructions.
Drain the spaghetti.
Divide the cooked spaghetti among deep plates, top with a generous portion of the minced meat and leek mixture, and finish with a teaspoon of sour cream.