Avocado and Caramelized Onions Panini

Sour dough bread -  4 slices
Avocado - 1 smashed with a sprinkle of salt
Onion - 1/2 of a large one thinly sliced
Any kind of shredded cheese - 2 handfuls OR
Any cheese -  4 slices

To customize your panini
Red Chili flakes
Basil leaves
Thinly sliced tomatoes

Saute the onions in some oil or butter with some salt and pepper until nicely browned and soft. Smear half of the avocado onto a slice of bread. Top it with one or more of your custom items, half of the onions and cheese.  Top with another slice of bread and make a panini of it.
I used a stainless steel plate and a heavy pan as my panini maker.