The big sell of a steak sandwich is that it's a steak sandwich. And yet, what makes any steak sandwich truly great is everything else between those two slices of bread (and maybe the bread, too). I don't mean to suggest that the steak isn't special; of course it is. It's just that it's a known quantity. The real interest lies in the condiments.
It's with that in mind that I devised the varied sauces and toppings for this one. My goal was to hit as many flavors and textures as I could. I wanted sweet and tart, bitter and savory, creamy and crisp, meaty and jammy. And so I set to work. The result was this baby, with roasted cherry tomato jam, a creamy-tart anchovy-spiked sauce, and a bright radicchio salad.
The first step was to roast the tomatoes, which I drizzled with olive oil and popped into a 350°F oven until they burst and their juices concentrated. Once they had cooled a little, I scraped them into a mixing bowl and stirred in fresh olive oil, along with some vinegar for extra brightness and minced thyme leaves for a woodsy, herbal flavor.
While the tomatoes were cooking, I made a sharp, creamy sauce by blending mayo and sour cream with anchovies, grated Parmesan cheese (for savory notes), and vinegar, along with a generous dose of freshly ground black pepper.
The final components were a simple salad of thinly sliced radicchio, which is mildly bitter, and flat-leaf parsley leaves, as well as some rapid-pickled onions and a few shavings of Parmesan cheese. I layered all of it on slices of lightly oiled and toasted country bread.
What about the steak? Easy—go with whatever tender steak you want (you can consult our guide here). Flank, hanger, skirt, strip, flap, tri-tip, you name it. Sear it until it's medium-rare, let it rest for at least five minutes—though there's also nothing wrong with cooking the steak in advance and cooling it down completely (and, on that note, you could even just use leftover steak)—then slice it thinly.
Like I said, it's about the steak, but only in the most general sense.