The Best And Worst Items On The Secret Menu At In-N-Out

Getting a mustard-grilled cheeseburger involves cooking the burger patty on one side, then squirting some mustard on the other side before flipping it.

The mustard becomes caramelized on the grill and seeps into the meat patty itself. This adds a tangy kick to the burger and the caramelization adds more savory notes.

Spicy lovers should consider adding chopped chili peppers to their In-N-Out cheeseburger, which are actually pickled cascabella peppers.

These yellow peppers look similar to banana peppers but are much spicier. Sources say the pickled cascabella peppers the chain uses is from the brand El Pato.

For onions on your burger without the sharp flavor of raw onions, ask for a whole grilled onion, which ensures a good flavor without too much crunch.

It comes with a grilled cross-section cut of the onion so you get intact rings instead of chopped pieces, providing sweetness and char while retaining the sharpness of raw onion.

In-N-Out's root beer float is a combination of root beer and their vanilla milkshake, but you can also opt for a different milkshake flavor if you prefer.

In-N-Out's staff will fill a milkshake cup halfway with the milkshake and top it off with some root beer. It's not as thick as a normal root beer float, but it's still pretty good.

A lesser known low-carb option on In-N-Out's secret menu is the whole grilled onion wrap, which includes a slice of onion with intact rings that have been caramelized.

For the onion wrap, two whole grilled onion slices sandwich the meat patties and cheese slices instead of the regular buns. It's messy to eat, but full of good flavor.