Peel the sweet potatoes. Slice them into bite-sized pieces, about ¾ inch thick. Wash, trim, and remove any bad spots.
Preheat a large skillet over medium-high heat. Add 1 tablespoon of butter and let it melt.
Add sweet potatoes to the skillet and sprinkle with about ½ teaspoon cinnamon. Stir to coat.
Turn the heat down to medium-low and let the sweet potatoes cook for 3–4 minutes while prepping apples.
Peel, core, and slice apples into bite-sized chunks, similar in size to sweet potato pieces.
Stir sweet potatoes, then add apples directly to the skillet. Add another ½ tablespoon butter and sprinkle another ½ teaspoon cinnamon on top.
(Optional) Sprinkle brown sugar over the mixture if a sweeter dish is desired; otherwise, simply rely on the natural sweetness of apples and sweet potatoes.
Continue cooking and stirring for another 3–4 minutes, until both sweet potatoes and apples are tender and lightly caramelized (taste a sweet potato piece to check doneness).
Turn off the heat, transfer to a serving bowl, and enjoy immediately—no oven space required!