Don't overcook the green beans. We're blanching them, which means you should boil them until the color turns bright green, then promptly remove them from the water and cool them down. This way, they stay that bright, beautiful color, and are crisp-tender.
Keep the heat medium, and stir the mushrooms frequently to avoid burning the garlic.
Butter, vegan butter, or your favorite cooking oil can be used instead of olive oil.
Serve with fresh lemon wedges if you like, or add a squeeze of lemon juice just before serving.
Store leftovers in an airtight container in the fridge for up to 3 days. They can be reheated in the microwave or in a skillet.