Slice the loaf open and spread the pesto onto both sides. Add the sliced muenster cheese, followed by the arugula, sliced tomatoes seasoned with salt & pepper, sliced peaches and provolone cheese.
Heat a grill pan or panini press with a drizzle of olive oil. Grill the sandwich for about 3 minutes per side on a pan, or for about 5-6 minutes total in a panini press until the cheese melts.