Step 1: Add the ingredients to a saucepan. Bring to a rolling boil, then turn heat to low and simmer (covered) 10 minutes.
Step 2: Carefully transfer to a heat-safe high-powered blender like a Vitamix...
... and blend until the soup mixture is fully smooth and creamy like this!
Step 3: Pour this into 3-4 (8-oz.) mason jars and cover with canning lids. Let cool completely on the counter before moving to the fridge to set.
After chilling at least 1-2 hours, you'll have a thickened ready-to-use dairy-free and gluten-free cream of mushroom sub perfect for all the casseroles!