Heat the oven to 200 C. Line a baking sheet with parchment.
Trim zucchini. Halve lengthwise. Scoop the center with a spoon and chop the scooped flesh.
Brush the halves with one tablespoon oil. Set on the sheet hollow side up.
Warm the remaining oil in a skillet on medium. Add onion and cook until soft.
Stir in garlic. Add chopped zucchini flesh and cook until most moisture lifts.
Fold in tomatoes and olives. Cook two minutes. Take the pan off the heat.
Add feta oregano and cumin. Stir so the cheese softens and clings.
Mix in lemon zest half the lemon juice parsley and basil. Taste and season with salt and pepper.
Fill each zucchini half with the warm mixture. Press gently. Top with breadcrumbs if using.
Bake for 25 to 30 minutes until the halves feel tender and the tops look lightly golden.
Finish with the remaining lemon juice and a pinch of herbs. Serve warm.