Preheat oven to 350°F (175°C). Line a 9x13 baking dish with parchment paper for easy cleanup and clean portions.
In a skillet over medium heat, brown the turkey breakfast sausage until no pink remains, breaking it into small crumbles, 6–8 minutes. Set aside to cool slightly.
In a large mixing bowl, whisk together the whole eggs and egg whites until well combined. Whisk in the cottage cheese until mostly smooth.
Add shredded cheddar, cooked sausage, onion, and bell pepper. Season with salt and black pepper, then stir to evenly distribute.
Pour the mixture into the prepared baking dish and spread evenly. Sprinkle the top generously with everything bagel seasoning.
Bake for 30–35 minutes, until the center is set and the edges are golden. It will puff slightly and settle as it cools.
Let cool completely at room temperature for at least 30 minutes for food safety and clean slices.
Cut into 5–6 equal squares and transfer to glass meal prep containers. Label with the date.