Heat a Dutch over medium heat, Add in onions and saute for about 2 minutes, onions will be translucent.
Add in garlic and stir for about another minute.
To the pot, add cubed butternut squash, sweet potatoes, vegetable stock, cinnamon, ground black pepper, and salt.
Simmer for about 45 minutes. Squash and potatoes should be fork tender.
Use an emulsion blender to puree the soup. Can use a blender also. NOTE: if using a blender, puree soup in batches. Be careful, as the soup is hot. Use a towel to hold over cover while blending the soup.
Check the seasoning and adjust, if needed.
Soup is ready to serve. Can be kept in the fridge for about 4 days.
Soup also freezes well.