The Double Jack features two quarter-pound beef patties, two slices of American cheese, lettuce, tomatoes, ketchup, mustard, mayo, pickles, and onions on a butter-toasted bun. While the whole setup sounds pretty basic and not-so-exciting, it's meant to serve as a platform to highlight some of the menu changes at Jack in the Box meant to result in tastier, fresher food.
The Double Jack is a roughly Whopper-sized burger in width but stands a bit taller due to the double patties but also because each patty felt just a bit bigger and beefier than the Whopper patty. I know some of you don't like the current grill seasoning they sprinkle on the burger patties while cooking, so you'll be happy to know that, as far as I can tell, they've gone back to plain old salt (and maybe pepper). I happen to like the current grill seasoning but you can't really go wrong with salt and pepper. Plus, it pushed the beef more to the fore.
While there were three different sauces, they were applied very modestly so that they didn't overwhelm any of the other components.
When it comes down to it, the Double Jack I tried offered a number of small improvements that make for a very good rendition of your standard fast food cheeseburger but with a lot more heft due to the extra beef. It'll be interesting to see how these turn out at the restaurant level.