This is my own recipe and it is always a big, big hit. I prefer the eggplant variant, but with zucchini so abundant this time of year...
Appetizer or Main Dish
Zucchini, Tomato, Mozzarella and Basil Caprese “Sandwiches” (vegetarian)
1 cup fresh basil leaves, 1 big clove garlic, 1 tablespoon parmesan cheese, 1/4 cup olive oil, 1/3 cup pine nuts (walnuts also work fine). Combine all in mini-food processor, grind up. You can use a blender instead. Slivers of nuts and small pieces of basil should still be visible in the finished product.
Select large zucchini, but not baseball bat sized. Slice into rounds ~1/4 inch thick. Alternatively, if the zucchini is small (so the rounds would be tiny) or huge (so the seeds must be removed), you can slice the zucchini lengthwise instead. Dredge in beaten egg, then in breadcrumbs. Place in single layer on greased cookie sheet, bake in 350 degree oven until brown on both sides (flip once). You can drizzle a small amount of olive oil on them before baking, if you wish. Or, you could fry the rounds instead (which admittedly is more yummy), but this way is much easier, healthier and less messy - and they still come out great.
Spread pesto on one side of each zucchini round. Place half of zucchini in single layer on cookie sheet. Top each zucchini round with a slice of mozzarella (can also use shredded mozzarella if you prefer), a slice of tomato, and sprinkle with parmesan cheese. Top each with a “pestoed” zucchini round. Bake in 350 degree oven until hot.
You can leave out the mozzarella and just use parmesan, you can spread 1 can of canned chopped tomatoes (ie, the flavored type, such as those made by Delmonte) in a baking pan (rather than a cookie sheet) and place the zucchini rounds on top (you can also spill a little on top of each sandwich after assembling), and/or you can serve the “sandwiches” with a side of tomato sauce or canned chopped tomatoes. Finally - you can use eggplant instead of zucchini - if you do, peel the eggplant before breading.