Vegetarian Layered Sandwich

1 large round loaf bread
6 large Portobello mushrooms
Olive oil, for brushing
Salt and freshly ground black pepper
1 large fennel bulb, thinly sliced
7 medium tomatoes, sliced
1 small red onion, thinly sliced, and rings separated
2 large yellow peppers, roasted, peeled, and cut lengthwise into thick slices
basil leaves
your favorite salad dressing

Cut bread in half horizontally. Pull out the bread from crusts, leaving 1/4-inch bread border. Cover crusts; set aside.
Thinly slice mushrooms and fennel. Brush or drizzle with olive oil; sprinkle with salt and pepper. Grill until tender, 2 to 4 minutes per side.
Arrange filling in bottom of bread: First, cover with half the tomatoes, then half the onions. Sprinkle with salt and pepper; drizzle with 3 tablespoons dressing and cover with basil.
The second layer is made up of half the mushrooms, then salt and pepper, dressing and basil.
The third layer is peppers, salt and pepper, dressing, and basil.
The fourth layer is the remaining mushrooms, salt and pepper, dressing, and basil.
The fifth layer is fennel, salt and pepper, dressing, and basil. The last layer is the remaining tomatoes, onions, salt and pepper, dressing, and basil.

Place top of bread on bottom half, enclosing vegetables. Wrap with plastic and let stand 45 minutes.
Unwrap sandwich. Using a large serrated knife, cut into wedges. Since it needs to rest for so long, it is a great picnic sandwich, but remember to take your serrated knife!

source: Martha Stewart