Italian Beef Dip Recipe

Prepare onions

Peel and thinly slice 2 medium yellow onions into half-moons so they cook evenly.

Heat a large skillet over medium-low heat. Add 2 tbsp olive oil and 1 tbsp unsalted butter. When the butter melts and foams, add the sliced onions, 1 tsp granulated sugar and 1/2 tsp kosher salt. Stir to coat.

Cook the onions slowly over medium-low to medium heat, stirring every 3–5 minutes to prevent sticking. After about 15 minutes they will soften and begin to brown; continue cooking another 10–15 minutes until deeply golden and sweetly caramelized (total 25–35 minutes). If the pan dries out, add a splash of water to deglaze and scrape up browned bits.

In the last minute of cooking, stir in 1 tsp balsamic vinegar (optional) to brighten the flavor. Remove from heat and set aside until assembling the sandwiches.

In a small bowl, combine 1/2 cup mayonnaise, 1 minced garlic clove, 1 tbsp fresh lemon juice, 1/2 tsp Dijon mustard, 1/4 tsp kosher salt and 1/8 tsp black pepper.

Whisk until smooth and taste — adjust lemon, salt or garlic as desired. Cover and refrigerate until ready to assemble. The aioli can be made up to a day ahead to let flavors meld.

In a small saucepan over medium heat combine 1.5 cups low-sodium beef broth, 2 tbsp red wine (if using), 1 tsp Worcestershire sauce and 1 tsp soy sauce. Bring to a gentle simmer.

Simmer uncovered for 8–10 minutes to concentrate the flavors slightly. Taste and season with 1/4 tsp kosher salt and 1/8 tsp black pepper as needed.

If you prefer a slightly thicker jus, whisk 1 tsp cornstarch into 1 tbsp cold water to make a slurry, then whisk it into the simmering broth and cook 1–2 minutes until it lightly thickens. Off heat, whisk in 1 tbsp unsalted butter for sheen. Keep warm until serving.

Preheat a panini press or heavy skillet/griddle over medium heat. If using a skillet, have a second heavy pan or a weighted press ready.

Brush the cut sides of the 2 ciabatta rolls lightly with 1 tbsp olive oil. Spread a generous layer of garlic aioli on both the top and bottom cut sides.

On the bottom half of each roll, layer half of the sliced roast beef (about 5 oz per sandwich), then divide the caramelized onions evenly over the roast beef.

Top the onions with the sliced brie (about 2 oz per sandwich). Sprinkle each sandwich with a pinch of fresh thyme leaves, 1/4 tsp kosher salt divided (about 0.25 tsp total divided across sandwiches), and a light grind of black pepper.

Close the sandwiches. Spread about 1 tbsp softened butter across the outside faces of each roll (the buttered sides will contact the grill).

Grill on the panini press for 3–5 minutes, or in the skillet: place sandwiches butter-side down in the hot skillet, press with the weighted pan, and cook 3–4 minutes per side until the bread is golden-brown and the brie is melted. Adjust time as needed to avoid over-browning. If cheese hasn't melted, tent with foil for a minute.

Remove sandwiches from heat, let rest 1 minute, then slice in half. Serve immediately with warm au jus in small bowls for dipping.