Panini are one of those great foods that is all about techniques with unlimited variations. Here is a pastrami and havarti cheese, with mayo and horseradish, one of my favorites.
This one was done with pugliese, but most any kind of bread will work, try Eastern flatbread for something different, or slice a baguette lengthwise.
For fillings, whatever you have on hand. Tomatoes, mushrooms, spinach, onions, garlic, peppers, olives, eggplant, zucchini; really most any will work. Sliced beef, chicken, thin pressed ground lamb, salmi; again let your imagination run.
Melted cheese is one of life’s pleasures so any cheese works just fine.
Fill the bread, coat outside with butter or olive oil, then grill until golden with pressure. A panini pan is well worth the price, I have a Calphalon.
Yet for years I used a regular fry pan with a cast iron skillet for the press.
Making panini is another of those techniques that are simple, yet produce excellent results and wonderful variety.