Steakhouse-Style Beef Tenderloin Sandos

• Toss potatoes on a baking sheet with a large drizzle of oil, half the garlic powder (you’ll use the rest later), salt, and pepper. Roast on top rack until browned and tender, 20-25 minutes.

• Meanwhile, in a small microwave-safe bowl, combine shallot, vinegar, 1⁄2 tsp sugar, and 1⁄2 tsp salt (1 tsp sugar and 1 tsp salt for 4 servings). Cover tightly with plastic wrap and microwave until shallot is softened, 30-60 seconds. • Stir, then refrigerate until ready to use in Step 5.

• Pat beef* dry with paper towels; season all over with remaining garlic powder, a big pinch of salt, and pepper. • Heat a large drizzle of oil in a large pan over medium-high heat. Add beef and cook to desired doneness, 4-7 minutes per side. • In the last minute of cooking, add half the garlic herb butter (you’ll use the rest later). Baste the beef by gently tilting the pan and spooning melted butter over beef. • Turn off heat; transfer beef to a cutting board to rest.

• While beef cooks, in a large bowl, toss arugula with 1 TBSP olive oil, 1 tsp shallot pickling liquid, a pinch of salt, and pepper (2 TBSP olive oil and 2 tsp shallot pickling liquid for 4 servings). • Spread remaining garlic herb butter onto cut sides of bottom halves of baguettes. Place gouda on cut sides of top halves. Place baguette halves, cut sides up, on a second baking sheet; bake on middle rack until cheese melts and bread is toasted, 2-4 minutes. • In a second small bowl, whisk mayonnaise with as much truffle seasoning as you like.