Brown: Add the oil, "butter", sage, and (optional) onions to a soup pot on medium heat. Sautee until butter is a light caramel color (about 4-5 minutes).
Simmer: Mix the corn starch into the veggie stock. Add the rest of the ingredients including the veggie stock mixture to the pot, bring to a boil, then turn heat to low and allow to simmer for about 5 minutes.
Blend: Carefully pour soup into blender. Remove center of blender lid (to allow steam to escape) and place lid on blender. Holding clean towel over hole in lid, blend on med-high until soup has visibly lightened in color and appears smooth
Top: Add optional toppings, or use as a vessel for your favorite sandwich.
Store: This soup stores great in the fridge for 3-4 days. Frozen, it can last up to 3 months.