lbs sweet potatoes, washed, peeled, and cut into 2'' chunks
(8-oz) cans pineapple chunks, drained but liquid reserved
cup dark brown sugar
tsp ground cinnamon
tsp ground nutmeg
stick butter, melted
cups walnut pieces, toasted
Place the potatoes and pineapple in a large bowl; set aside. Combine the brown sugar, cinnamon, nutmeg, butter, and molasses in a separate medium-size bowl, then add the mixture to the sweet potatoes. Toss to coat. Spoon the potatoes into a 4-qt (or larger) slow cooker and cook on high about 2-1/2 to 3 hours, or until the potatoes are soft. Gently stir every half hour. Make a slurry by quickly whisking the cornstarch and pineapple liquid together in a small bowl. Slowly add the slurry; gently, but thoroughly, mix to combine. Bring the potatoes to a simmer and continue to simmer for 3-5 minutes. Reduce the temperature to low or keep warm. Carefully fold in the walnuts, being careful not to break apart potatoes. Serve warm.