Slice a white part of the leek into slivers. Wash the zucchini, cut lengthwise and slice thinly. Peel and crush the garlic, cut cherry tomatoes and olives in half.
Heat olive oil in a cast iron frying pan, cook leek and zucchini slices until golden. Add garlic cloves, halved olives, mediterranean spice mix and fry about 1 more minute.
In a bow whisk eggs with salt and pepper, stir in crumbled feta. Add halved tomatoes to the frying pan and pour egg-feta mixture over. Put cherry tomatoes branch in the middle of frittata (if using). Set the heat to low and cook for 5-7 minutes.
Transfer the skillet to the oven and bake at 400F for 7-10 minutes or until the top of the frittata is set and golden. For nicely browned top, put frittata under the broiler for 1-2 minutes at the end of cooking.
Remove from the oven and let stand for 5-6 minutes before cutting into wedges. Garnish with freshly chopped basil leaves. Enjoy!