Cheesy Truffle Steak Tip Sandwiches

Remove the butter from the refrigerator to soften. Preheat the oven to 450°F. Wash and dry the fresh produce. Halve the potatoes lengthwise. Halve the baguettes. Halve, peel, and thinly slice the sweet or yellow onion. Grate the fontina on the large side of a box grater. Roughly chop the balsamic onions. Quarter and deseed the lemon. Roughly chop the pistachios.

Line two sheet pans with foil. Transfer the potato pieces to one sheet pan. Drizzle with olive oil and season with salt, pepper, and enough of the spice blend to coat (you may have extra). Toss to coat and arrange in an even layer. Roast 17 to 19 minutes, or until browned and tender when pierced with a fork. Remove from the oven. 

Meanwhile, place the halved baguettes on the remaining sheet pan, cut side up. Evenly spread the softened butter onto the cut sides. Toast in the oven 5 to 7 minutes, or until lightly browned and crispy. Leaving the oven on, remove from the oven.

Meanwhile, pat the steak tips dry with paper towels. Season with salt and pepper. In a medium pan (nonstick, if you have one), heat a drizzle of olive oil on medium-high until hot. Add the seasoned steak tips in an even layer. Cook, without stirring, 2 minutes. Continue to cook, stirring occasionally, 1 to 3 minutes for medium-rare (125°F), or until browned and cooked to your desired degree of doneness.* Leaving any browned bits (or fond) in the pan, transfer to a plate. 

*The USDA recommends a minimum safe cooking temperature of 145°F for steak. Cook the steak tips an additional 2 to 3 minutes to achieve this.

Heat the pan of reserved fond on medium-high until hot (if the pan seems dry, add a drizzle of olive oil). Add the sliced onion; season with salt and pepper. Cook, stirring occasionally, 3 to 5 minutes, or until lightly browned and softened. Add the worcestershire sauce (carefully, as the liquid may splatter). Cook, stirring frequently, 30 seconds to 1 minute, or until the onion is browned and the liquid has been absorbed. Turn off the heat.

Top the toasted baguette bottoms with the cooked steak, caramelized onion, and grated fontina. Leaving the sandwiches open, toast in the oven 2 to 3 minutes, or until the cheese is melted. Remove from the oven; carefully transfer to a cutting board. Finish the sandwiches using the toasted baguette tops, then halve on an angle. In a large bowl, combine the arugula, chopped balsamic onions, roasted potatoes, half the parmesan, the juice of 2 lemon wedges, and a drizzle of olive oil. Toss to combine. Taste, then season with salt and pepper if desired. Serve the finished sandwiches with the salad on the side. Garnish the salad with the chopped pistachios and remaining parmesan. Serve the remaining lemon wedges on the side. Enjoy!