Generously butter the bottom and lower sides of a 6-quart slow cooker.
Butter
In a bowl, whisk together the pumpkin puree, eggs and brown sugar. Whisk in the evaporated milk, pumpkin pie spice, vanilla and salt until smooth.
15 oz pumpkin puree, 2 large eggs, 3/4 cup packed light brown sugar, 12 oz evaporated milk, 2 tsp pumpkin pie spice, 1 tsp vanilla extract, 1/4 tsp salt
Pour into the slow cooker. Cover and cook on High, beginning to check for doneness at 2 hours.
Continue cooking as needed, checking every 10–15 minutes, until the middle is set and a toothpick inserted near the center comes out mostly clean, without wet custard. The center should reach at least 160°F on a food thermometer. Mine was done at exactly 2½ hours.
Turn off the heat and remove the lid. Let stand for approximately 20 minutes before scooping.
If a little liquid has pooled beneath the filling, use a slotted serving spoon to lift out portions, leaving the liquid behind. Carefully spoon out and discard any remaining pooled liquid.
Serve with whipped topping or whipped cream and a sprinkle of cinnamon.
whipped topping or whipped cream, ground cinnamon