In a large pot, bring together the sweet potatoes, 1½ cups of apple cider, kosher salt, and the cinnamon stick. Add enough water to cover the potatoes completely.

Heat the pot over medium-high until it reaches a boil. Then, reduce to a simmer and let it cook for 20-30 minutes, or until the sweet potatoes are fork-tender.

Once tender, drain the sweet potatoes and return them to the pot, discarding the cinnamon stick.

Add the remaining ½ cup apple cider, butter, sour cream, and an additional pinch of salt to the sweet potatoes.

Use a potato masher or fork to mash until creamy and smooth. Adjust seasoning with more salt and freshly ground black pepper as desired.

Transfer the mashed sweet potatoes to a serving bowl. Top with crispy onion strings and sprinkle with fresh parsley. Enjoy warm!