In a large pot, saute onion, garlic, celery and carrots over a medium to medium high heat until translucent, about 3-5 minutes.
Add seasonings and saute for one minute, then add flour and saute for another 1-2 minutes.
Add vegetable broth and plant milk to deglaze the pan, then add potatoes, stir, cover, and bring to a boil.
Stir again, reduce to a simmer and cook until potatoes are soft, about 10-12 minutes.
Keep the soup chunky, mash it with a potato masher, blend with an immersion blender or transfer to a blender or food processor to make it a smooth, pureed soup. Remove the bay leaf before serving or blending [note#1].
Season with salt and pepper, serve immediately, and garnish to your preference.
Enjoy!
Video
Notes
I either partially mash my soup directly in the pot, or blend half with a blender and return it to the pot (this second way is my favorite).