Preheat the oven to 375℃/190℃. In a large bowl, whisk together the eggs, yogurt, oregano, and salt. Set aside.
Heat the oil in a 10-inch to 12-inch oven-safe skillet over medium-high heat. Add the sausage and onion and cook, stirring occassionally until they begin to brown, about 5 minutes. Add the spinach and cook just until wilted. Remove skillet from heat.
Pour the egg mixture over top and lighlty stir to evenly spread out the spinach and sausage. Sprinkle the Parmesan on top.
Bake in the center of the oven for 25 miutes, or until the eggs have set and the top is golden. Cut into 6 slices and serve.
Notes
Flanagan, Shalane & Kopecky, Elyse (2018) Run Fast Cook Fast Eat Slow Rodale Publishing