In a large skillet or dutch oven, saute onions in butter until tender and golden brown, about 25 minutes. Remove with a slotted spoon. Add flour, salt and pepper to skillet; stir until smooth.
Gradually stir in milk until blended.
Bring to a boil; cook and stir for 2 minutes or until thickened. Reduce heat to medium.
Return onions to the pan; heat through.
Recipe by Let's Be Yummy at http://letsbeyummy.com/2013/11/24/creamed-onion-gluten-free-dairy-free/