Spinach & Pepper Egg White Frittata Squares
A tray of egg whites and cottage cheese baked with spinach and bell peppers, then cut into eight squares that keep in the fridge for the week and taste good cold or warmed through.
Why it works
Egg whites are close to pure protein, delivering the essential amino acids, including leucine, that trigger muscle protein synthesis, without the fat and cholesterol carried in the yolk. Cottage cheese adds casein, a slow-digesting protein that keeps amino acids available in the blood for hours rather than all at once, useful when a square is eaten on its own instead of alongside other protein. Folding cottage cheese into the whites also keeps the bake moist: egg whites alone tend to turn rubbery in the oven, and the cheese's curds and liquid soften that texture without adding back the saturated fat a whole egg would. Bell peppers contribute vitamin C in amounts that rival citrus, and spinach adds folate and vitamin A as carotenoids, rounding out a dish that is otherwise almost entirely protein. Skipping the yolk means skipping its choline and most of its vitamin D, so this frittata works best as part of a week that includes whole eggs somewhere else.
The muscle-protein-synthesis role of leucine and the value of spreading protein across meals both rest on well-replicated exercise-nutrition research. The idea that this egg-white version beats a whole-egg frittata on cardiovascular outcomes has not been tested directly; it follows from the general, well-supported link between lower saturated fat intake and LDL cholesterol.
Ingredients
- 3 cups (710 ml) liquid egg whites (about 20 large egg whites)
- 1 1/2 cups (340 g) low-fat cottage cheese
- 1 tbsp olive oil, plus more for the pan
- 1 small yellow onion, diced
- 2 red bell peppers, diced
- 150 g (about 3 cups packed) baby spinach, roughly chopped
- 2 cloves garlic, minced
- 1/2 tsp salt
- 1/4 tsp black pepper
- 1/2 tsp dried oregano
Method
- Heat the oven to 180C (350F) and line a 9x13-inch baking dish with parchment, or oil it well so the squares release cleanly.
- Warm the olive oil in a skillet over medium heat and cook the onion and peppers for 5 to 6 minutes until soft. Add the garlic and spinach and cook just until the spinach wilts, about 2 minutes, then set aside to cool slightly.
- Whisk the egg whites and cottage cheese together with the salt, pepper, and oregano. Small curds of cottage cheese are fine; it does not need to be smooth.
- Fold the cooled vegetables into the egg mixture and pour into the prepared dish, spreading it into an even layer.
- Bake for 28 to 32 minutes, until the center is set and no longer wet and the edges are just turning gold. Cool for 10 minutes before cutting into 8 squares.
