Pat the 6 oz steak dry with paper towel. Season both sides evenly with 1 tsp salt and 1/2 tsp freshly ground black pepper. Let rest at room temperature for 20–30 minutes while you prepare other components.

Prepare garlic butter for baguette

In a small bowl, combine 2 tbs softened butter with 2 minced garlic cloves and a pinch of salt. Mix until smooth. Slice the baguette lengthwise but not completely through so it opens like a book (or cut into two halves). Spread garlic butter evenly on the cut sides.

Cook the steak

Heat a heavy skillet or cast-iron pan over high heat until very hot. Add 1 tbs olive oil and swirl to coat. Add the steak and sear without moving for 2–3 minutes until a deep brown crust forms. Flip and cook another 2–3 minutes for medium-rare (internal temp about 125–130°F / 52–54°C). For medium, cook 3–4 minutes per side. In the last 30 seconds, add 1/2 tbs butter to the pan and spoon melted butter over the steak. Remove steak to a cutting board and let rest for 5–7 minutes before slicing thinly against the grain.

Toast the garlic baguette

While the steak rests, place the buttered baguette cut-side up on a baking sheet. Broil or bake at 400°F (200°C) for 4–6 minutes until the butter is melted and edges are golden; if broiling, watch closely to avoid burning. Remove and slice into serving-length portion(s).

Assemble the baguette

Spread 1 tbs Dijon mustard on the bottom half of the toasted baguette. Layer a handful (about 1/2 cup) of arugula or lettuce if using. Thinly slice the rested steak and arrange evenly on the bread. If desired, add 1 tsp whole-grain mustard on top of steak for extra texture. Close the sandwich and press lightly. Cut in half if preferred.

French Fries

Prep potatoes

Peel the russet potatoes if desired (skin on is fine), then cut into 1/4–1/3-inch (6–8 mm) sticks for classic fries. Rinse the cut fries in cold water until the water runs clear to remove excess starch. Drain and pat completely dry with clean towels or paper towels.

Cook fries (pan-fry or shallow fry method)

In a heavy skillet, add about 1 cup oil and heat to medium-high (about 350–375°F / 175–190°C). Add potatoes in a single layer working in batches if necessary. Fry, stirring occasionally, for 6–8 minutes until golden and crisp. Using a slotted spoon, transfer fries to a paper towel-lined plate to drain. Alternatively, for extra crispness, fry twice: blanch at 300°F (150°C) for 4–5 minutes, remove and drain, then raise oil to 375°F (190°C) and fry 2–3 minutes until golden.

Season fries

While still hot, sprinkle fries with 1 tsp fine salt, 1/2 tsp garlic powder, and 1 tbs chopped parsley (optional). Toss gently to distribute. Squeeze a little lemon over the fries if using.

Finishing & Service

Plate the steak baguette with a generous portion of garlic-toasted French fries on the side. Serve with extra Dijon and whole-grain mustard on the plate for dipping. Serve immediately while steak and fries are hot.