Preheat the oven to 375°F (190°C). Prepare a baking sheet by lining it with parchment paper.

Wash and dry the zucchinis thoroughly. Slice each zucchini in half lengthwise and scoop out the flesh.

Drizzle the hollowed zucchini halves with olive oil and season with salt and pepper. Arrange them cut-side up on the baking sheet.

In a skillet, heat olive oil over medium heat. Add chopped red onion and minced garlic, sautéing until translucent.

Add the reserved zucchini flesh to the skillet and cook for an additional 2-3 minutes.

Mix in quartered cherry tomatoes, Kalamata olives, salt, and pepper. Cook until the tomatoes begin to soften.

Remove from heat and stir in crumbled feta, oregano, cumin, parsley, lemon zest, and lemon juice.

Fill each zucchini half with the mixture, adding breadcrumbs if desired.

Drizzle filled zucchini with olive oil and bake for 25–30 minutes until tender and tops are golden brown.

Allow to cool slightly, then drizzle with additional lemon juice and garnish with fresh herbs before serving.