Place beans in a Multipurpose Steamer. Cover and microwave on high for 5 min.
Meanwhile, in a bowl, whisk together milk, mayonnaise and seasoning.
Stir seasoning mixture into green beans. Cover and microwave for 10 min on high, stirring once halfway through. Or bake, uncovered, in a preheated 350°F oven until warm and bubbly, about 30–35 min.