Trim the ends of the fresh green beans and wash them thoroughly. Pat them dry with paper towels to remove excess moisture.
Preheat your air fryer to 380°F (190°C) for a few minutes to ensure it's hot and ready for cooking.
In a large bowl, toss the green beans with olive oil until evenly coated. This helps to ensure that the beans crisp up nicely in the air fryer.
Place the coated green beans in the air fryer basket in a single layer. Cook them at 380°F (190°C) for 8-10 minutes, shaking the basket halfway through to ensure even cooking. The green beans should be tender and slightly charred around the edges.
While the green beans are cooking, prepare the garlic butter sauce. In a small saucepan, melt butter over medium heat. Add minced garlic and cook until fragrant and golden brown, about 2-3 minutes. Remove from heat.
Once the green beans are done cooking, transfer them to a serving bowl and pour the garlic butter sauce over them. Toss gently to coat the green beans evenly with the sauce.
Transfer the Green Beans with Garlic Butter Sauce to a serving platter and garnish with freshly chopped parsley or a sprinkle of Parmesan cheese, if desired. Serve hot as a delicious side dish or appetizer.