Pellkartoffeln mit Quark is a typical North German dish, often eaten for light summer lunches but it really is popular anytime. Quark does not exist in most countries so Germans abroad will forever be.
Philly Stuffed Peppers, super easy high protein low carb - I know that this is not vegetarian, but not everyone I know is so this might be a great buffet or pot luck dish! You could use any high protein meat in these, like chicken or turkey!
One Pot Zucchini Mushroom Pasta - A creamy, hearty pasta dish that you can make in just 20 min. Even the pasta gets cooked in the pot. I would skip the parmesan and heavy cream for marinara or EVOO instead.