Heat a large skillet over medium heat. Once hot, add 1 teaspoon of olive oil, then crumble the sausage into the pan.
8 ounces turkey breakfast sausage, 1 tablespoon olive oil
Cook until the sausage is no longer pink, then drain on paper towels.
In the same pan over medium-low, heat the remaining 2 teaspoons of olive oil. Once hot, add the onions, potatoes, and seasoned salt. Sauté, stirring occasionally, for about 5 minutes.
1 tablespoon olive oil, ½ cup onion, 3 small Yukon Gold potatoes, 1½ teaspoons seasoned salt
Cover, reduce the heat to low, and cook, stirring occasionally, for 5 more minutes or until the potatoes can easily be pierced with a fork and the onions are soft.
Add the spinach, black pepper, and cayenne pepper. Stir for a minute or so until the spinach wilts. Add in the sausage and remove from heat.
2 cups raw baby spinach, ¼ teaspoon freshly ground black pepper, ⅛ teaspoon cayenne pepper
Preheat the oven to 400°F. Spray a 12-count muffin tin with cooking spray.
Divide the sausage mixture evenly between the muffin cups. Let it cool for 5 minutes or so, then sprinkle each muffin cup with 1 tablespoon of cheese.
12 tablespoons shredded cheddar cheese
In a medium bowl, whisk together eggs and yogurt, then divide evenly between the muffin cups.
8 large eggs, ½ cup plain yogurt
Bake for 20 minutes or until the muffins are puffy, set, and golden brown, then remove from the oven.
Let cool for 10 minutes. After, run a rubber spatula around each frittata and remove from the pan.