Heat oil or vegan butter in a large skillet over medium heat.
- Add mushrooms and cook for 6–8 minutes, stirring occasionally, until browned and soft.
- Add garlic and shallot (or onion). Cook another 2–3 minutes until softened and fragrant.
- Sprinkle in flour and stir to coat the mushrooms. Cook for 1–2 minutes.
- Slowly pour in vegetable broth while stirring constantly to avoid lumps. Bring to a gentle simmer.
- Add Dijon mustard, tamari, salt, and pepper. Simmer for 5–7 minutes, stirring occasionally, until thickened.
- Add white beans and fresh herbs (if using). Simmer for another 3–4 minutes to heat through.
- Stir in plant-based cream or milk if using. Taste and adjust seasoning as needed.
- Serve warm over mashed potatoes, grains, or with crusty bread. Garnish with herbs if desired.