Add a few inches of water to a medium pot fitted with a steamer basket. Bring to boil.
Place sweet potatoes in steamer basket. Cover, reduce heat to medium, and steam until fork-tender 20–30 minutes (depending on size).
Allow sweet potatoes to cool enough to handle. Scoop out flesh and place in a bowl. You will need 1.5 cups of cooked sweet potato.
Add all ingredients to blender, except honey. Blend on high until smooth.
Adjust sweetness with honey and thin with more milk, if desired.
Notes
Optional add-ins: ½ cup plain silken tofu (adds protein) ¼ cup oatmeal soaked in the milk for 10 minutes (adds fibre) ½ tsp freshly grated ginger (adds flavour) 1 tbsp almond butter (addsprotein)
Cut very large sweet potatoes in half in reduce steaming time
Sweeten with honey, maple syrup, a couple of dates, or leave plain
Substitute your favourite spices for pumpkin spice if you don't have it
Pecan butter may be nice, if available (I couldn't find any at my grocery)
Leftover smoothie can be kept in the fridge for the next day. Cover with plastic wrap or put in an air-tight container.