Fill a 3-quart pot with water three-quarters full.
Peel the sweet potato completely.
Slice into 1/4-inch thick slices.
Add into the pot and put over medium/high heat.
Allow the sweet potatoes to boil, then reduce to a simmer.
Continue to cook until they are soft when poked with a fork, about 15 to 20 minutes.
Strain off the sweet potatoes from the water.
Using a potato masher, mash up the potatoes in the pot (this is the easiest way!). Or, alternatively, you can chop into small cubes (the smaller the better).
Store in an airtight container in the fridge for up to 7 days.
Video
Notes
Tips
Make sure to peel skin completely. While the skin can be healthy for humans, dogs cannot digest it well and it can cause GI upset.