Set the sous vide to 167°F (75°C) and allow it to come to temperature while you prepare the egg mixture.
In a blender or food processor combine 8 egg whites, 5 tablespoons cottage cheese, 1/4 cup shredded Monterey Jack, 1 tablespoon feta, 1 tablespoon cold butter, 1 teaspoon cornstarch, and 2 dashes Tabasco. Blend until completely smooth and slightly aerated.
Add 1 teaspoon finely chopped red bell pepper and 2 teaspoons chopped green onion tops, then pulse a few times just to incorporate and lightly chop the vegetables.
Spray four half-pint mason jars with nonstick spray. Divide the blended egg mixture evenly among the jars, leaving a little headspace. Wipe jar rims clean and secure lids fingertip-tight.
Carefully lower the jars into the preheated sous vide bath and cook at 167°F (75°C) for about 60 minutes, or until the egg bites are completely set. If they seem undercooked, continue for another 5 minutes.
Remove jars from the water, carefully open, and run a knife around the edges if needed to release the egg bites. If desired, place the tops under a hot broiler briefly until the cheese browns.