Add the green beans to a pan of boiling water and simmer for 3-4 minutes until crisp and tender. Drain completely and set aside to steam dry.
Step 2
Melt the butter in a skillet over a medium heat. Thinly slice the mushrooms and crush the garlic. Add to the pan along with the beans, lemon juice, lemon zest, salt and pepper. Stir well to combine.
Step 3
Sauté for 4-5 minutes or until the mushrooms are cooked through and golden. Remove from the heat and sprinkle over the grated Parmesan and toss to combine.