Vegetarian sandwiches don’t generally generate too much excitement. But longtime foodie Natalie Aczon says that at her restaurant, Caffe Aczione, that dish was the most popular menu item.

Aczon opened the popular eatery along Kala­kaua Avenue near Makaloa Street with her brother Errol. The name of the restaurant was a play on their last name and the Italian word for “action.” During the cafe’s run from 1993 to 1998, Errol “was the assembler of these much-ordered sandwiches,” Aczon said.

The siblings’ interest in food no doubt came from their late father, Moses, who was an executive chef at the Hickam Officers’ Club, Ilikai Hotel and the Garden Court restaurant at the old Liberty House in Ala Moana Center.

Aczon invented this sandwich, combining roasted vegetables with fresh onions, tomatoes and lettuce, then adding basil pesto, mayonnaise and Dijon mustard. She baked her own soft focaccia bread, and made her pesto from scratch.

You may already be familiar with Natalie Aczon. She’s worked for Whole Foods Market, Jamba Juice, Starbucks, Mahina & Sun’s, TBD …, Chopchop Rotisserie, and now, Honolulu Baking Co. It’s easy to tell she loves to cook and be around food.

Today, she still makes bread, though now it’s an easy, no-knead focaccia recipe from Bon Appetit that she considers simple and delicious. She bastes the bread with a mixture of olive oil and melted butter for even more flavor.

Her pesto recipe uses sweet basil leaves and walnuts, which she prefers over traditional pine nuts because they have a stronger taste and are more economical. With a food processor, the pesto is made within minutes.

But folks who want to streamline the process can buy bread and prepared pesto without short-changing themselves — this sandwich will still be amazing.

Aczon roasts locally grown long eggplant, zucchini and sweet red bell peppers. The vegetables can be made up to two days prior to serving.

Mozzarella cheese is also in the mix. Aczon says if you prefer the sandwich hot, use a harder version of the cheese; if eating it at room temperature, use softer fresh mozzarella.

She advises not omitting any of the ingredients, as each has a purpose.

“At the cafe, a customer might ask us to omit the thinly sliced onions or mayonnaise,” she said. “And I would always say, ‘Please try it as it is. Then if you don’t like one part, you can take it out.’”

The magic: Herbs atop the focaccia add to the other flavors. Roasted vegetables are tender while still maintaining their structure. Fresh tomato slices, the bite of fresh raw onion and the sweet crunchiness of the lettuce provide contrast to the softness of the bread.

The finishing touch: one fresh basil leaf, torn and added to each sandwich. “That’s the secret — that freshness from the torn basil,” she said. “Don’t leave it out; it is essential. You can tell the difference.”

CAFFE ACZIONE VEGETARIAN SANDWICH

• 3 long eggplants, sliced 4-inches long and 1/4-inch thick
• 3 zucchini, sliced 4-inches long and 1/4-inch thick
• 2 sweet red bell peppers, sliced into 1/2-inch-wide strips
• 3 to 4 tablespoons virgin olive oil, plus more to grease pan and top bread
• Salt and pepper, to taste
• 1 (9-by-13-inch) loaf focaccia bread
• Melted butter, as needed
• Dijon mustard, as needed
• 1 head romaine (or other lettuce), cut into 4-inch pieces
• 1 large tomato, sliced into 1/4-inch rounds
• 1 Maui onion (or other sweet onion), thinly sliced
• Mayonnaise, as needed
• 8 teaspoons basil pesto (recipe follows)
• 8 fresh basil leaves
• 8 slices mozzarella cheese

Heat oven to 425 degrees. Coat eggplant, zucchini and bell pepper in olive oil, salt and pepper. Coat baking sheet with more oil. Place vegetables on sheet and bake until brown, about 5 minutes per side. Prepare vegetables up to two days prior to serving; keep refrigerated.

Brush top of bread with 50-50 mixture of melted butter and olive oil. Cut bread into 8 pieces, each about 4-by-4-1/2 inches. Then slice each piece in half horizontally through the center.

Spread top half of each bread piece with Dijon mustard, then stack with a lettuce leaf, tomato slice and sliced onion.

Spread bottom half with mayonnaise and 1 teaspoon pesto. Layer with eggplant, red pepper and zucchini. Tear one sweet basil leaf into pieces and place on zucchini. Top with 1 slice mozzarella. Sprinkle with more salt, if desired. Place in oven to melt cheese if you prefer.

Put both halves together and cut diagonally. You may need to anchor the sandwich with toothpicks.

Repeat to assemble 8 sandwiches. Each sandwich feeds 1 or 2 people, depending on side dishes.

Approximate nutritional information, per sandwich (not including olive oil, butter, mayonnaise, mustard): 750 calories, 44 g fat, 23 g saturated fat, 135 mg cholesterol, 1,400 mg sodium, 41 g carbohydrate, 7 g fiber, 12 g sugar, 47 g protein.

BASIL PESTO

• 1-1/2 cups fresh basil leaves
• 2 to 4 garlic cloves
• 1/8 cup lemon juice
• 1/8 to 1/4 cup olive oil
• 1/4 cup walnuts or pine nuts
• 1/4 cup Parmesan cheese

Place all ingredients in food processor and process until blended. Use immediately or cover with olive oil and refrigerate. Use within a week. Makes about 1 cup.

Approximate nutritional information, per 2 tablespoons (including 1/8 cup oil): 70 calories, 7 g fat, 1 g saturated fat, 5 mg cholesterol, 50 mg sodium, 2 g carbohydrate, 2 g protein, no fiber or sugar.

Lynette Lo Tom, author of “Back in the Day,” is fascinated by old-fashioned foods. Contact her at 275-3004 or via Instagram at @brightlightcookery. Nutritional analysis by Joannie Dobbs, Ph.D., C.N.S.