Start by washing and finely dicing your medium zucchini. The smaller the dice, the better the relish will cling to the crostini, creating a delightful texture contrast.
Heat 1 tablespoon of olive oil in a skillet over medium heat. Add the diced zucchini and sprinkle in the garlic powder, salt, and pepper. Cook for about 3 to 4 minutes, stirring occasionally, until the zucchini softens slightly but still retains a bit of crunch. Remove from heat and let it cool slightly.
Once the zucchini has cooled, transfer it to a small mixing bowl. Add 1 teaspoon of freshly squeezed lemon juice and 1/4 cup of grated Parmesan cheese. Stir gently to combine all the flavors, ensuring the zestiness of the lemon brightens every bite.
Preheat your oven to 375°F (190°C). Arrange the sliced French baguette pieces on a baking sheet. Toast them in the oven for about 7 to 10 minutes, or until they’re golden and crisp.
Once the baguette slices are toasted and cooled slightly, spoon generous amounts of the lemon-Parmesan zucchini relish onto each slice. Sprinkle the chopped fresh basil leaves over the top for an aromatic finish.
Arrange your crostini on a serving platter and enjoy immediately. These are best served fresh to retain the crispness of the bread and the brightness of the relish.