Blanch the Green Beans: Bring a large pot of salted water to a boil. Add green beans and cook 2 to 3 minutes, until bright green and just tender-crisp. Drain immediately and transfer to a bowl of ice water to stop cooking. Once cooled, drain well and set aside.
Toast the Garlic: Heat olive oil in a 12-inch skillet over medium heat. Add garlic slices and cook 2 to 3 minutes, stirring often, until lightly golden and fragrant.
Finish the Dish: Add drained green beans to the skillet and toss to coat in garlic oil. Season with salt and pepper.
Garnish & Serve: Transfer to a serving platter, sprinkle with parmesan cheese, and finish with a squeeze of lemon juice if desired. Serve warm.
Notes
Make-Ahead: Blanch green beans up to 24 hours ahead. Store in an airtight container in the refrigerator, then finish in the skillet before serving.Storage: Store leftovers in the fridge up to 3 days in an airtight container.Reheating: Warm in a skillet with a drizzle of olive oil over medium heat until hot, or microwave in short bursts. Note: parmesan may clump slightly on reheating.Freezing: Not recommended once cooked. To freeze ahead, blanch beans, dry well, and freeze on a baking sheet. Transfer to a freezer-safe bag or container for up to 3 months. Finish in the skillet when ready.Ingredient Note: To trim fresh green beans, snap or cut off just the stem end (the part that was attached to the plant). The tapered tail end is tender and does not need to be removed unless preferred.