To do so, divide ground sausage into as many balls as you have muffin cups (12, for a standard pan). Press each ball into the cup to cover the bottom and come up the sides.
Depending on what you want in your bowl, you can either blind-bake the cups or add fillings before they go into the oven. Eggs make a great filling and can bake with the sausage.
You can either scramble the eggs first or crack a whole egg into each cup. The latter will only work if you're using a standard or larger-sized muffin pan.
Add other fillings like cheese, cooked potatoes, onions, or peppers, and bake the cups at 350 degrees F for roughly an hour, or at 400 degrees F for about 10 minutes.
If you decide to go eggless, simply bake the empty sausage cups until the meat is cooked, which takes about 10 minutes. Once cooked, fill with cheese and cooked veggies.