Heat a skillet to medium heat and spray with cooking spray. Finely dice red onions and add to the pan.
Next, add in turkey sausage. Season with some salt and pepper to your liking.
While that's cooking, finely dice the other vegetables.
Preheat the oven to 350 degrees F.
Once the turkey is browning, add the diced peppers and jalapeno to the skillet. Note: You may need to add more cooking spray here. Make sure the meat is completely cooked prior to turning off the heat.
In a separate bowl, add eggs, egg whites, and cottage cheese. Whisk until smooth.
Spray a 9x13 Pyrex dish with cooking spray and pour the meat + veggies into the Pyrex pan. Add in chopped spinach and stir around.
Pour the egg mixture into the dish and lightly mix everything.
Top with cheddar cheese and bake for 30-35 minutes or until the middle of the frittata is thoroughly cooked.
Let cool, slice, and enjoy!