Preheat the oven to 400°F (200°C). Grease a 9×9-inch round baking dish or other oven-safe pan with 2 tablespoons olive oil and place the dish on a parchment-lined baking sheet.
In a blender or using an immersion blender, blend 1/2 cup cottage cheese until smooth, then transfer to a large mixing bowl.
Add 16 ounces egg whites, 1 cup halved cherry tomatoes, thinly sliced red onion, 1 cup chopped baby spinach, 2 minced garlic cloves, 1 teaspoon Italian seasoning, 1/2 teaspoon salt, and 1/2 teaspoon black pepper to the bowl; whisk until well combined.
Pour the mixture into the prepared baking dish, spreading it evenly.
Bake in the preheated oven for 30 minutes, or until the egg whites are set and the top is lightly golden.
Remove from the oven and let the frittata cool slightly before slicing into 4 servings.