1. Preheat the oven to 375°F. Cook the pasta according to package directions until al dente, drain and set aside.
2. Meanwhile, wash the leeks and cut into thin rings. Slice the ham into strips. Remove and finely chop the leaves from the thyme sprigs. Heat the butter in a skillet over medium heat and sauté the leeks and thyme for 5 minutes. Lower the heat and add the ham, sour cream and half of the cheese. Season with salt (in moderation) and pepper.
3. Fold the pasta into the leek mixture. Spoon into ramekins and divide the rest of the cheese on top. Bake in the oven until golden brown, 15 minutes.
Per serving: 515 calories, 21g fat, 13g saturated fat, 59mg cholesterol, 852mg sodium, 56g carbohydrate, 3g fiber, 6g sugar, 26g protein