Chop and puree chimichurri ingredients together until it forms a sauce. Add salt and pepper to taste.
Season steak with salt and pepper. Preheat pan on high heat, then drizzle one tablespoon of olive oil and sear filet until it is caramelized on both sides. Let rest for 5 minutes.
While steak is resting, prepare the garnish. Poach tomatoes in boiling salt water for about two minutes, until the skin begins to wrinkle.
Immediately shock in cold water to stop the cooking process, then peel off the skin. Set aside until ready to serve.
Char shishito peppers in a skillet until blistered.
To serve, set the steak in the middle of the plate and top with the tomato and charred shishito peppers. Season by drizzling with chimichurri.