Finely chop the onions.Melt butter in a medium skillet over medium-high heat.Add onion and cook until softened, about 5 to 7 minutes. Let cool till warm and not hot.Transfer onions to a food processor and add remaining ingredients.Pulse several times until onions and cheese are well combined and smooth.Cover and refrigerate for a couple hours or overnight until firm.You can top with poppy seeds or sesame seeds or dehydrated onions, if you like.