Combine sour cream, green onions, mustard and thyme together and mix well
Spread one side of each piece of bread with butter and the other with the sour cream mixture
Place several slices of turkey (depending on thickness), a slice of cheese and tomato on the side of the bread with the sour cream mixture
Place sandwich butter side down in a skillet and brown on both sides
Serve warm
Feel free to add some extras to these sandwiches such as thin sliced red onion, lettuce, sprouts, olives and pickle slices