Calfornia Grilled Veggie Sandwich

I'm always on the lookout for good vegetarian recipes. This one is great. I've made it a couple of times now - including for my sister and my dinner co-op - and it has been thoroughly enjoyed every time!

I think the sauce really makes this sandwich what it is. The bread helps, too. This recipe is slightly adapted from a highly-rated one I got on All Recipes. The original calls for foccacia bread which I've tried and is good. I prefer (homemade) ciabatta because the flavor of the sauce and veggies really comes out that way. You can also swap veggies (add mushroom or eggplant) and cheeses (feta, provolone, Parmesan...) to suit your desires.

Ingredients:
Sauce -
1/4 cup light mayonnaise
3 cloves garlic, minced
1 tablespoon lemon juice

Sandwich -
1 T. olive oil
1 red bell peppers, sliced
2 small zucchini, sliced
1 red onion, sliced
1 small yellow squash, sliced
Good bread (foccacia, ciabatta, etc...)
Your choice of cheese (optional; I've used Parmesan and Provolone)

Directions:
1. In a bowl mix sauce ingredients (mayo, garlic, lemon juice); refrigerate until ready to use.
2. Preheat grill or broiler.
3. In a separate bowl, toss veggies with olive oil until all are coated.
4. Grill or broil, turning as necessary and watching carefully until veggies are done to your likely.
5. Assemble sandwich: put sauce on bread, top with veggies, add cheese (if desired).
6. Enjoy the vegetarian goodness!