Add the vegan butter to a large pot or Dutch oven and heat over medium heat. Once melted, add the onion and sauté for a few minutes.

Add mushrooms, thyme, rosemary, sea salt, and pepper. Cook for 7-10 minutes until mushrooms release moisture and begin to brown. Add garlic and cook for another minute.

Add cornstarch and stir to coat the vegetables. Then add tamari and mustard, stirring again.

Add the vegetable broth and potatoes, bring to a boil. Once boiling, reduce heat and simmer uncovered for 15-20 minutes, or until potatoes are tender, stirring occasionally.

Stir in the beans and dairy-free milk and simmer uncovered for another 10-15 minutes until vegetables are tender and stew thickens. Adjust seasoning and thickness as needed.

Serve warm, optionally garnished with parsley and a sprinkle of freshly cracked black pepper.