Melt 1 tablespoon dairy-free butter in a skillet over medium-high heat.
Add the celery and saute for 10 to 15 minutes. Set aside.
In a medium saucepan melt the remaining ½ cup butter over a medium-low heat.
Add in flour and whisk together until well combined.
Add vegetable broth and dairy-free milk, whisk until smooth, about 1-2 minutes.
Season with salt, pepper, garlic powder and onion powder.
Bring to a simmer and cook until it begins to thicken, about 3-5 minutes, If it becomes too thick you can add a more dairy-free milk.
Add the sauted celery. Heat through.
Remove from heat and serve or allow to cool completely if storing.
Store in airtight container in refrigerator.