Preheat your oven to 375°F (190°C).
In a medium mixing bowl, whisk together the large eggs, egg whites, Greek yogurt, sea salt, and black pepper until the mixture is completely smooth and well-combined.
Heat the olive oil in a 10-inch oven-safe skillet over medium heat.
Add the diced zucchini and minced garlic to the skillet, sautéing for 3-4 minutes until the zucchini is slightly tender and fragrant.
Stir in the halved cherry tomatoes and chopped fresh chives, spreading them evenly across the bottom of the pan.
Pour the egg mixture over the vegetables in the skillet, ensuring the vegetables remain evenly distributed.
Sprinkle the crumbled feta cheese and chopped fresh basil over the top of the egg mixture.
Transfer the skillet to the preheated oven and bake for 15-18 minutes, or until the center of the frittata is set and the edges are lightly browned.
Remove from the oven and let the frittata rest for 5 minutes before slicing into wedges and serving.