Place olive oil and garlic in a large skillet. Fry (stirring occasionally) over a medium heat until the garlic is golden brown; approximately 2 minutes.
Add eggplant and zucchini to the skillet, fry until the eggplant is brown and tender; approximately 5 to 7 minutes.
Add the tomato chunks to the skillet, stir the mixture until the tomato becomes a pulp. Mix in salt, oregano, and basil. Stir the entire mixture over the heat for 2 minutes, then remove pan from heat and let the mixture cool.
Preheat oven to 325 degrees F (165 degrees C).
Slice the bread into 12 (1-inch thick) slices. Distribute garlic powder and butter evenly over the top of each slice. Place the slices directly onto the oven rack (do not use a cookie sheet, the bread will get crisper this way). Let the bread heat for 3 to 5 minutes.
Remove the bread from the oven and arrange them on a serving platter. Spread the vegetable mixture over the 12 bread slices, distribute the topping as evenly as you can. Serve immediately.