First, properly set the water level in your Sous Vide Supreme by placing the perforated grill plate on top of the baking rack in the Sous Vide Supreme. Fill 4 ramekins with water and arrange them on the grill plate. Fill sous vide with just enough water to come within 1/4" of the top of your ramekins.
Remove ramekins and dry well. Set aside.
Preheat Sous Vide to 195°F/90.5°C
Grease ramekins with butter and set aside.
In a small saucepan, add heavy cream and whisk in pumpkin pie spice. Heat over medium low heat until cream starts to bubble around the edges. About 10 minutes.
While cream is heating, use a stand mixer to whisk egg yolks, pumpkin, coconut sugar, vanilla and salt until evenly incorporated throughout.
Slowly pour cream mixture into egg mixture and whisk together until evenly combined.
Divide mixture evenly between the four ramekins and cover ramekins with foil.
Place ramekins on grill plate in your sous vide and cook for 90 minutes.
Remove ramekins and let come to room temperature then refrigerate 4 hours or even overnight before serving.
When ready to serve, sprinkle 1 tbs coconut sugar evenly over custard and caramelize with a kitchen torch or under a broiler.
If you don't have a sous vide supreme, simply follow the same directions and then place filled ramekins on a sheet pan in an oven preheated to 350°F and bake for 30 minutes.