In a bowl, mash avocados & lime juice. Stir in garlic, onion & cilantro: blend well. Ser aside.
Paninis
Slice red onion thinly. In a saucepan, add butter & heat to melt. Add onion & sprinkle with salt. Cook until onion has softened. Remove from heat & set aside.
Slice cheese & butter one side of each slice of bread.
With buttered sides down, Generously spread guacamole over the 4 slices of bread. Divide the turkey slices between 2 of the slices. Next, divide the cheese & place it on the turkey along with the red onion. Place the 2 remaining slices on top with the buttered side on the outside.
Grill on panini maker until heated through & crispy on the outside. Serve.
Recipe Notes
If a panini grill is not available just use an ordinary skillet to get the job done!