Preheat the oven to 350°F. Lightly coat a 1 1/2- quart oval baking dish with nonstick spray.
In a 12- inch skillet, cook the onion and garlic in butter over medium heat for 3 minutes or until softened. Stir in the green beans and thyme. Cook for 4 minutes or until the onions begin to brown. Add the broth. Bring to boiling. Cook, stirring occasionally, for 3 to 4 minutes or until the broth is nearly evaporated. Add the whipping cream and nutmeg. Cook for 4 minutes or until the mixture begins to thicken. Transfer to the prepared baking dish. Stir in half of the cheese, all of the salt & pepper, and then sprinkle with the remaining cheese.
Bake, uncovered, 15 to 20 minutes or until the beans are tender- crisp.
If preparing this recipe as gluten-free, just be sure to use a brand of chicken broth that is known to be GF.
You may also sub trimmed and halved brussels sprouts for the beans. Increase the baking time to 20 to 25 minutes.