Panini with grilled zucchini and mushroom-chive mayonnaise

A note on panini breads: you can buy or make foccacia or ciabatta rolls, which are the traditional choices for panini. We have also had great success with sourdough, light rye, and--believe it or not--thinly sliced bagels (pictured). If you don't have a panini press, seriously consider acquiring one, as they're fairly inexpensive--I use mine constantly.  My children (even the mushroom-hater) love this sandwich, so that's a definite plus for any quick meal!

This recipe comes from the book Panini Express--which I love. 
Mushroom mayonnaise
8 oz white button mushrooms, wiped clean and finely minced
1 t. chopped fresh chives
3 T. mayonnaise
2 t. lemon juice
salt and pepper to taste

For the sandwich
2 zucchini (you could also add in an eggplant; treat it exactly as you would the zucchini--I love grilled eggplant and I save the leftovers to use on pizza)
White cheese (we've used provolone, Swiss, mozzarella, Monterey Jack, and Gouda with equal enjoyment on this particular sandwich.  Gouda is pictured.)

Saute the mushrooms in olive oil until they begin to release their juices (2 minutes).  Sprinkle with the lemon juice and continue to cook another 3-4 minutes until they're brown (brown as in cooked down, not brown as in getting crunchy and burned).  Remove from pan and let cool, then mix in mayonnaise, chives, and salt/pepper.

Slice zucchini (or eggplant) lengthwise in 1/4 inch thick strips.  Brush each side with olive oil (I simply use spray olive oil from a can--less mess!) and sprinkle with salt and pepper.  Grill on a panini press until browned and softened, approximately 5 minutes.

Compose the sandwich by spreading mushroom mayonnaise on one slice of bread, layering in the zucchini, then topping with the cheese and another slice of bread.  Grill on the press until browned and golden, approximately 3-5 minutes, depending on your press.