I can only speak for Kefalonia but there you can get courgette balls (Kolokithokeftedes) everywhere; in every tavern and restaurant. There are really creamy with tasty feta and a hint of fresh mint.
Wash, dry the courgettes and then grate them. Place them in a colander with some salt and leave them for at least 30min to get rid of the excessive water. After 30 min squeeze them with your hands to get the water out, wait another 30min and squeeze them again.
In the meantime, peel and crush the garlic, peel and grate the red onions and trim and finely chop the spring onions.
Finely chop both of the herbs; fresh mint and parsley.
In a large bowl add the courgettes, onions, garlic, spring onions, fresh herbs, eggs, black pepper, a pinch of salt and the two tbsp. of extra virgin olive oil. Mix well and then crumble the feta cheese into the mixture with the breadcrumbs and flour. Add more breadcrumbs or flour if the mixture is not firm enough to make balls.
Fry
Form the courgette balls and fry them in quite a bit of oil at medium/high heat. Fry them for about 5 min on each side until they are coloured. The courgette balls should be crispy on the outside and should have a creamy and rich texture on the inside.
Take them out of the pan and place them on kitchen paper to absorb some of the cooking oil.
Bake
Fill muffin moulds and bake them at 200ºC for 25-30 min.
Air-Fry
Air fry them for 13min at 200ºC and then for 2 min at full temperature 240ºC.