In a 10-inch cast iron skillet over medium/high heat, add the breakfast sausage and break up with a spatula. Continue to cook until sausage is fully cooked, about 10 minutes. Remove from heat.
Slice mushrooms and set aside.
In a large bowl, whisk the eggs and bone broth together.
Add the sliced mushrooms to the egg mixture and stir together.
Transfer the egg mixture to the skillet with the sausage.
Bake for 20 to 25 minutes, or until the eggs look set.
Video
Notes
Tips
If you don't have bone broth, just use milk in its place.
You can use turkey breakfast sausage or even bacon in place of the pork sausage.
Make sure the frittata is done by looking for visual signs that the eggs are fluffy, a golden yellow color and not giggly in the center.