French Dip Recipe

Heat a large skillet over medium heat. Add 1 tbsp olive oil and 1 tbsp unsalted butter. When butter foams, add the thinly sliced onions and 1/4 tsp kosher salt; stir to coat.

Cook the onions, stirring every 3–5 minutes, adjusting heat to keep them at a gentle sizzle (reduce to medium-low if browning too fast). After 15 minutes add 1 tsp brown sugar (optional) to deepen color and flavor. Continue cooking 15–20 more minutes until onions are deeply golden and soft. Total time about 30–35 minutes. Remove from heat and set aside.

In a small saucepan set over medium heat combine 3 cups beef broth, 1 tbsp beef base (or demi-glace), 1 tsp soy sauce, 1 tsp Worcestershire sauce, 1 tsp minced garlic and 1/4 tsp black pepper.

Bring to a gentle simmer and cook 6–8 minutes to meld flavors. Taste and adjust seasoning with salt or more soy/Worcestershire if needed. Stir in 1 tbsp unsalted butter just before serving for a glossy finish. Keep warm; reserve 1/2 cup for the aioli and transfer the rest to a small serving bowl for dipping.

In a small bowl combine 1/2 cup mayonnaise, 1/2 cup warm au jus, 1 tsp Dijon mustard, 1 tsp lemon juice, 1/4 tsp finely minced garlic, 1/4 tsp black pepper and 1/8 tsp salt.

Whisk until smooth and emulsified. Taste and adjust with more jus (thin slightly) or more mayo (thicken) to reach a spreadable consistency. Refrigerate briefly if not using immediately.

Slice Dutch crunch rolls horizontally, keeping a hinge if desired. Lightly butter cut sides with the reserved 2 tbsp unsalted butter.

Heat a large skillet or griddle over medium-high heat and add 1 tbsp neutral oil. Season the thinly shaved filet with 1 tsp kosher salt and 1/2 tsp freshly ground black pepper and toss to coat.

Working in batches if necessary, sear the shaved beef in the hot skillet just until browned and warmed through, about 1–2 minutes (no need to fully cook through since cuts are thin). Remove beef to a plate and keep warm in a low oven (200°F / 95°C) or tent with foil.

Place the buttered roll cut-sides down on the skillet and toast until golden and crisp, about 1–2 minutes.

Build each sandwich: spread 1–2 tbsp au jus aioli on the bottom roll, layer 3–4 oz warmed shaved beef, top with a mix of Gruyère and Swiss slices (approx. 2 oz Gruyère + 1 oz Swiss per sandwich). Spoon a generous portion of caramelized onions over the cheese.

If you want melted cheese: place assembled sandwiches open-faced on the skillet or under a broiler for 1–2 minutes just until cheese melts.

Close sandwiches, slice in half if desired, and serve immediately with a small bowl of warm au jus for dipping alongside.