Preheat your oven to 375°F (190°C).
Finely chop the broccoli and cauliflower florets into small, uniform pieces.
Heat the olive oil in a 6-inch or 8-inch oven-safe non-stick skillet over medium heat.
Add the broccoli and cauliflower to the skillet and sauté for 4-5 minutes until they are tender-crisp and slightly browned.
In a medium mixing bowl, whisk together the large eggs, egg whites, sea salt, black pepper, and garlic powder until well combined.
Pour the egg mixture over the sautéed vegetables in the skillet, ensuring they are evenly distributed.
Cook on the stovetop for 2-3 minutes without stirring, allowing the edges to set.
Transfer the skillet to the preheated oven and bake for 10-12 minutes, or until the center is firm and the top is lightly golden.
While the frittata is baking, portion the Greek yogurt into a small bowl and top with the fresh mixed berries.
Carefully remove the skillet from the oven, slice the frittata into wedges, and serve alongside the berry yogurt bowl.