I love the taste or caramelized onion and it is a flavor that pairs well with cheese. At Cheesetique, one of our most popular cheeses was a caramelized onion cheddar. I think you get a better flavor by caramelized the onions yourself and adding a nice Gouda. I picked up this Boerenkass raw milk farmstead Gouda at Trader Joe's for $7.99/lb. Boeren is Dutch for farmers and kass means cheese. This cheese is made with raw milk from cow's who live in the same place where this cheese is made. Most cheesemakers are not dairy farmers. Making cheese is hard, being a dairy farmer is harder, and doing both is awesomely difficult. But I think it makes for an exceptional cheese. the freshet milk makes the best cheese and some people think that the less the milk is agitate before making cheese the better the final product.
This grilled cheese was made using caramelized onion, Boerenkass, a touch of dijon mustard, and rye bread.