If you haven’t mashed sweet potatoes yet, add cubed sweet potatoes to a large stock pot and cover with water. Bring to a boil and cook for 15-20 minutes or until fork tender. Drain and mash with a masher, fork or food processor.

Preheat oven to 400°F and arrange a rack in the middle of oven. Lightly spray a mini-muffin tin with cooking spray and set aside.

In a large bowl, stir together the mashed sweet potatoes, eggs, ¾ cup grated parmesan cheese, rosemary, bacon, salt and pepper.

Fill each muffin cup all the way full with the mashed sweet potatoes mixture. Sprinkle the tops with the remaining 1/4 cup parmesan cheese.

Bake until the potato cups are set and browned on top, about 20 minutes. Let cool for about 5 minutes in the pan, then use a spoon or knife to gently release them from the pan. Serve immediately with dollops of sour cream or plain greek yogurt, if desired.