In my quest to try to eat more fish, I made some crispy fish sandwiches from tilapia filets. I think they would have been better with some lettuce and tomato but I had neither around so I just added some tartar sauce and a slice of white onion. If you like, you can soak onion slices in ice water while you’re fixing everything else. That takes a bit of the sharp flavor away and leaves you with a more mellow crunchy onion slice.
I don’t really measure when I mix up tartar sauce. I often make it with just mayonnaise, a bit of ketchup and lemon juice. Sometimes I add diced dill or sweet pickles. Sometimes I add capers. This batch had capers and I used half mayonnaise and half sour cream, as per a sauce I saw in a recent issue of Cooking Light , where I got the idea to make the fried fish sandwiches.