Melt vegan butter in a saucepan over medium-high heat. Add celery and onion and saute until vegetables are softened but celery still has a bit of snap, about 5 minutes. Season with parsley, sage, thyme, garlic powder, salt, pepper, rosemary, and marjoram. Cook and stir for 1 more minute. Stir in vegetable stock and bring to a boil, stirring occasionally. After it reaches a boil, remove from heat.