Adjust rack to middle position and preheat oven to 425 degrees. Wash and dry produce.

Halve, peel, and thinly slice shallot. Halve, core, and thinly slice apple. Halve lemon.

In a small bowl, combine vinegar, half the thyme, 2 TBSP water, ¼ tsp sugar, and a big pinch of salt until salt and sugar are dissolved. (For 4 servings, use all the thyme, 4 TBSP water, and ½ tsp sugar.) Stir in shallot; set aside to pickle.

In a separate small bowl, combine mayonnaise and mustard. Season Dijonnaise with salt and pepper to taste.

Pat beef* dry with paper towels; season all over with half the garlic powder (all for 4 servings), half the onion powder (all for 4), 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. 

Turn off heat; transfer to a cutting board to rest. Wipe out pan.

Heat a drizzle of oil in same pan over medium heat. Add pickled shallot and its liquid, stock concentrates, and ¼ cup water (⅓ cup for 4 servings). Cook, stirring occasionally, until shallot is softened, 4-5 minutes. 

Remove pan from heat; stir in 1 TBSP butter (2 TBSP for 4) until melted. Cover to keep warm.

Halve baguettes lengthwise. Toast directly on middle rack until crisp, 2-3 minutes. 

Thinly slice beef against the grain. 

Once baguettes are toasted, transfer to a baking sheet; arrange cut sides up. Top bottom halves with gouda and beef. Bake on middle rack until cheese is melted, 2-3 minutes; transfer to a cutting board.

Using tongs or a slotted spoon, arrange shallot from pan over melted cheese (reserve au jus in pan). Spread top baguette halves with Dijonnaise. Close sandwiches.

In a medium bowl (large bowl for 4 servings), combine mixed greens, apple, juice from half the lemon (whole lemon for 4), and 1 TBSP olive oil (2 TBSP for 4). Toss to coat. Season with salt and pepper to taste.

Halve sandwiches crosswise. Pour au jus into small serving bowls. 

Divide sandwiches and salad between plates. Serve with au jus on the side. TIP: We like to dunk our sandwiches in the au jus before each bite!