Start by rinsing and washing your veggies.
Cut zucchini into thick ribbons and bell pepper into strips (julienned).
In a small shallow dish marinate the red bell pepper in 1/4c of balsamic vinegar.
Note: Marinate peppers for 1 hour or longer (can be done the night before, the longer the better)
In a nonstick pan, griddle, or grill add olive oil and cook your zucchini on each side as well as the marinated bell peppers until nicely browned.
To a small dish add the Vegan Mayo and Balsamic Vinegar and mix and set aside.
Before you begin to prepare your panini warm up a pan to medium low heat, or begin to warm you griddle.
To assemble your panini, add some balsamic mayo to both pieces of bread, and layer the vegan mozarella cheese, zucchini ribbons, red bell peppers, and arugula. Top with the other slice of bread, mayo side down to complete the panini assembly.
Butter the top slice of bread, and place butter side down on warm pan or griddle and cover with a lid.
Grill or pan fry your sandwich on each side until golden brown and toasted.