Preheat the oven to 220C, fan-forced. Halve the unpeeled potatoes lengthwise. Put the potatoes in a medium saucepan of cold salted water and bring to the boil. Reduce the heat to medium and cook for 7-9 mins until just tender. Drain, reserving the pan.
Step 2 — Make salsa verde
While the potatoes are cooking, finely chop the parsley, including stems. Finely chop the capers. Finely chop garlic, then using the flat side of the knife, mash to a paste (adding a little salt to the garlic on the board helps). Combine parsley, capers, half the garlic, 1 tbs extra virgin olive oil and ½ tsp white wine vinegar in a bowl and season with salt and pepper.
Step 3 — Prep hasselback potatoes
Put the cooked potato halves, cut-side down, on a chopping board. To prevent cutting all the way through, put a skewer or chopstick on each side of the potato. Using a sharp knife, cut the potatoes widthwise at 3mm intervals, without cutting all the way through.
Step 4 — Roast hasselback potatoes
Melt 20g butter in the reserved pan over medium heat. Remove from the heat and stir in the remaining garlic. Line an oven tray with baking paper. Put the potatoes, cut-side down, on the lined tray and brush or drizzle with the garlic butter. Scatter with the breadcrumbs and season with salt and pepper. Roast for 10 mins or until golden and crisp.
Step 5 — Cook steaks
Meanwhile, heat a medium frypan over high heat (it's important to have the pan very hot before adding steak, otherwise it may stew slightly and become tough). Drizzle steaks with 2 tsp olive oil and season with salt and pepper. Reduce heat to medium-high and cook steaks for 2-3 mins each side for medium-rare, or until cooked to your liking. Remove from the pan and rest for 3 mins.
Step 6 — Get ready to serve
While the steaks are cooking, combine 1 tsp extra virgin olive oil and 1 tsp white wine vinegar in a large bowl and season with salt and pepper. Coarsely chop the tomato. Add tomato and salad leaves to the dressing and toss to combine. Divide steaks and any resting juices, hasselback potatoes and salad among plates. Drizzle steaks with salsa verde to serve.