We love anchovies, but if you don't, swap in 1 grated garlic clove for extra flavor in the marinade.
This recipe originally appeared in our Fall 2021 issue. Get the magazine here.
In a medium bowl, whisk the anchovies, mayonnaise, mustard, and vinegar. Slowly whisk in 1/2 cup oil until blended. Reserve 2 tbsp. dressing in the bowl.
Season steaks with salt in a shallow pan; coat with remaining dressing. Cover with plastic wrap and marinate at room temperature for up to 2 hours.
Preheat oven to 350°.
Remove steaks from marinade and pat with paper towels.
Heat 2 tbsp. oil in a large cast-iron pan over medium-high. Add steaks and cook until browned, 3 minutes; flip and cook 2 minutes more.
Transfer to a rimmed baking sheet and roast until medium-rare, about 7 minutes.
Discard all but 1 tbsp. fat from skillet. Lower heat to medium.
Add tomatoes and cook, stirring occasionally, until blistered, 6 minutes.
Toss tomatoes and onion with dressing in bowl. Thinly slice steaks, top with tomatoes, and garnish with oregano.