1. Wash the green beans thoroughly and snap or cut off the stem ends. You can leave them whole or cut them into 2-inch pieces.

2. Wipe the mushrooms clean with a damp paper towel or a mushroom brush. Slice the mushrooms to about 1/4-inch thickness. If they are very small, quartering them works well too.

3. Peel and mince the garlic cloves.

4. Bring a large pot of salted water to a rolling boil.

5. Add the trimmed green beans and cook for 2-4 minutes until they turn bright green and are slightly tender but still crisp.

6. Immediately drain the green beans and plunge them into an ice bath to stop the cooking process.

7. Once cooled, drain the green beans thoroughly and pat them dry.

8. Heat 2 tablespoon of olive oil in a large skillet over medium-high heat.

9. Add the sliced mushrooms in a single layer and let them cook undisturbed for 3-4 minutes.

10. Stir occasionally and cook for an additional 3-4 minutes until they are golden brown.

11. Season the sautéed mushrooms with salt and pepper to taste. Add red pepper flakes if using.

12. In the same skillet, add the remaining 1 tablespoon of olive oil over medium-high heat.

13. Add the minced garlic and sauté for about 30 seconds until fragrant.

14. Add the blanched green beans to the skillet and sauté for 3-4 minutes until they are heated through and slightly browned.

15. Return the sautéed mushrooms to the skillet with the green beans.

16. Add the soy sauce and toss everything together to combine and heat through.

17. If using, stir in the butter until melted and the vegetables are coated.

18. Taste and adjust the seasoning with additional salt, pepper, or red pepper flakes if desired.

19. Garnish with chopped fresh parsley or chives before serving.