Spread hummus on each of the slices of bread. Top one bread round with 2 pieces of bacon, 2 slices swiss cheese and 1/4 of the turkey, top with another bread round (hummus side down). Repeat with remaining ingredients to make 4 sandwiches. Butter the tops and place on the panini butter side down, spread other side with butter, repeat with remaining sandwiches. Close the panini press lid and cook until bread is browned and cheese is melted. Remove and eat immediately.
Notes
If you don't have a panini maker you can also use a griddle or frying pan.