* The recipe can easily be doubled in a 3-quart slow cooker or tripled in a large-sized crockpot. Cooking time may vary for larger batches.
* caramelized onions: can be done up to 48 hours in advance.
* gruyere: can be replaced with shredded white cheddar or provolone cheese for a more economical option!
* brie: can be replaced with another 4 ounces of cream cheese.
* make ahead: cook the dip without the gruyere in the slow cooker. Transfer to a baking dish, cover it, and refrigerate for up to 48 hours before serving. Remove from the refrigerator 1 hour before baking. Top with gruyere and bake at 350ºF covered for30-40 minutes or until everything heats through and the cheese on top melts.