Preheat a Panini press or George Foreman grill.
Spread ½ Tbsp. butter onto one side of each slice of bread.
On the unbuttered side of 4 slices of bread, evenly layer the goat cheese, figs, melon, prosciutto and arugula. Top with a buttered slice of bread.
Place the Paninis onto the preheated grill, (both slices of bread should be butter side out).
Cook for 10 minutes, or until bread is golden brown and cheese is slightly melted.
Slice in half and serve hot.