French-Ish Dip Pastrami Panini With Three Sharp Cheeses and Beer-Mustard Onions

A pressed, dunkable sandwich that nods to the French dip

Some sandwiches are built for neat bites; others are built for drama. The French dip—hot beef, melted cheese, bread sturdy enough to hold the filling, and a cup of au jus on the side—belongs firmly in the second category. It’s rich, savory, and intentionally messy in the best way: the whole point is to dip.

This “French-ish dip” panini keeps that dunkable, juicy spirit but takes a detour into deli territory. Instead of roast beef on French bread, the filling leans on deli-sliced pastrami and rye. The sandwich is then pressed panini-style so the exterior becomes crisp and the interior turns molten with cheese. The result is a hot sandwich that feels familiar if you love French dips, yet distinct if you’re also a fan of classic pastrami-on-rye.

Why pastrami works so well in a dip-style sandwich

Pastrami brings a specific kind of intensity: peppery, slightly smoky, and distinctly salty from its curing process. That bold profile can be the centerpiece of a sandwich rather than just another layer of deli meat. In this recipe, the pastrami is warmed directly in a seasoned broth, which does two jobs at once: it heats the meat gently and creates an au jus you can serve alongside the finished panini for dipping.

Because pastrami is naturally salty, the liquid matters. Using low-sodium beef broth helps keep the final sandwich from tipping into overly salty territory. It’s easier to add salt later than to take it away, and here the pastrami and cheeses already bring plenty of seasoning on their own.

The balancing act: three sharp cheeses plus sweet-tangy onions

Strong ingredients can either compete or harmonize. This sandwich aims for harmony by pairing pastrami with three sharp cheeses and then counterbalancing all that savory punch with onions that are caramelized and simmered with dark beer, mustard, and honey.

The cheese lineup is intentionally assertive: Cooper Sharp cheese, sharp cheddar, and fontina. Together, they create a layered melt—sharpness up front, richness through the middle, and a smooth, stretchy finish when pressed. If you want to stick closely to the intended flavor profile, this trio is the recommended route.

That said, the recipe is flexible about substitutions. If you prefer a different direction, you can swap in cheeses such as Swiss, Gruyère, mild cheddar, or Provolone. The key is choosing cheeses that melt well and complement the pastrami’s peppery bite.

The onion topping is where the sandwich gets its sweet-and-tangy counterweight. The onions start by softening and browning in butter. Then the pan is deglazed with dark beer—stout or porter—before mustard and honey are stirred in. As the mixture cooks down, it turns jammy, clinging to the meat and cheese rather than sliding out of the bread.

Dark beer in the skillet: what it adds (and what it doesn’t)

Dark beer is used here as a cooking ingredient rather than a beverage pairing. Simmering it down with onions builds a flavor profile that leans toasty and nutty with hints that can read as cocoa and caramel. The beer reduces until it has almost completely evaporated, and the alcohol cooks off, leaving the deeper roasted notes behind.

If you want to keep the flavor profile while avoiding alcohol entirely, an alternative approach is to use a combination of root beer and coffee. The idea is to capture similar roasted sweetness and depth without using beer.

Panini press optional: how to get the right texture without special equipment

A panini press is convenient, but it’s not required. What matters is consistent weight and even heat. You can cook the sandwiches on a grill pan and press them with a heavy skillet (a small cast-iron skillet works well as the “press”). If you don’t have a grill pan, two cast-iron skillets can do the job: the larger one for cooking, the smaller one for pressing.

The weight isn’t just for looks or grill marks. Pressing with steady, consistent pressure helps the bread crisp evenly and encourages the cheeses to melt into the pastrami and onions. You could toast the sandwich without pressing, and it would still taste good, but you’d miss the signature contrast: a crunchy exterior with a hot, melty interior.

Ingredients you’ll need

This recipe breaks down into three main parts: warming the pastrami in a seasoned broth (which becomes the dipping au jus), making the beer-mustard onions, and assembling/pressing the sandwiches.

• For the hot pastrami and au jus: low-sodium beef broth, prepared horseradish, minced garlic, fresh chopped rosemary, fresh chopped thyme, deli-sliced pastrami
• For the beer and mustard onions: salted butter, sliced yellow onion, dark beer (stout or porter), Dijon mustard, grainy mustard, honey
• For assembling the panini: rye bread, butter, Cooper Sharp cheese, sharp cheddar cheese, fontina

Note that the ingredient list intentionally avoids extra salt. Between the cured pastrami and the cheeses, the sandwich has plenty of seasoning without additional salting.

Step-by-step: how to make the French-ish dip panini

Plan to cook the pastrami and onions first, then build and press the sandwiches while everything is still hot. The au jus is reserved from the pot and served on the side.

• Place the broth, horseradish, garlic, rosemary, and thyme in a large pot. Stir to combine and bring to a simmer over medium heat.
• Once simmering, add the pastrami to the pot.
• Reduce the heat to low, cover, and cook for 15 minutes.
• Meanwhile, melt the butter in a large skillet over medium heat.
• Once melted, add the onions, and saute them until they begin to soften and brown, about 5 minutes.
• Deglaze the skillet with beer, stir to combine with the onions, and bring to a simmer.
• Simmer until the beer has almost completely evaporated, about 10 minutes.
• Add the Dijon mustard, grain mustard, and honey to the skillet and stir to combine.
• Continue to cook for 2 minutes until the onions become jammy. Remove from the heat and set aside.
• Place bread slices on a sheet of wax paper and spread butter over one side.
• Flip 4 of the bread slices over, butter side down.
• Divide the Cooper Sharp cheese between the 4 slices.
• Top the cheese with hot pastrami (let any excess au jus drip off the pastrami before transferring to the bread). Reserve the au jus.
• Top the pastrami with the onion mixture, spreading it out evenly.
• Top the onions with the cheddar and fontina cheese slices.
• Cap the sandwiches with the remaining bread slices, butter side-up.
• Preheat a panini press, panini pan, or grill pan over medium heat.
• Once hot, add the sandwiches. Firmly and evenly press the sandwiches (using either a sandwich press or a heavyweight pot or pan).
• Toast for 2 minutes or until golden brown on one side. Flip, press, and repeat on the other side until the sandwiches are toasty and the cheese has melted.
• Ladle the au jus between serving cups and serve alongside the sandwiches for dipping.

Serving notes: build for dipping

The au jus isn’t an afterthought—it’s part of the identity of this sandwich. Because the pastrami is warmed in a seasoned broth, you end up with a ready-made dipping liquid that echoes the flavors inside the panini. Ladle it into individual cups so each sandwich can be dipped as you eat.

When assembling, letting excess au jus drip off the pastrami before it hits the bread helps keep the sandwich press-friendly. The goal is a crisp exterior, and too much liquid inside the bread can make it harder to achieve that crunch. Dipping is where the sandwich gets juicy, not while it’s being pressed.

Equipment options and technique reminders

If you’re aiming for the classic panini texture—crisp outside, melty inside—focus on two technique points: medium heat and consistent weight. Medium heat gives the bread time to toast without scorching before the cheese fully melts. Consistent weight (rather than pressing down intermittently with a spatula) encourages even browning and a cohesive interior.

A dedicated press works, but a heavy skillet is a practical stand-in. A grill pan can add defined ridges, but it’s not mandatory. What matters most is that the sandwich is pressed evenly and toasted on both sides until the cheeses have melted.

Cheese choices: stick to sharp, or adjust to taste

The recommended trio—Cooper Sharp, sharp cheddar, and fontina—leans into boldness. It’s designed to stand up to pastrami and still be noticeable once the sandwich is dipped into au jus. If you substitute, choose cheeses that melt smoothly and won’t disappear behind the other strong flavors.

Options mentioned for swapping include Swiss, Gruyère, mild cheddar, or Provolone. Each will shift the sandwich slightly: Swiss and Gruyère can emphasize a more classic deli melt direction, while Provolone can soften the overall sharpness. Mild cheddar will reduce the bite if you prefer a gentler cheese profile.

Managing salt and intensity

Pastrami’s curing process makes it saltier than many other deli meats. That’s part of its appeal, but it also means the rest of the recipe should be built thoughtfully. Low-sodium beef broth is used specifically to keep the au jus from becoming too salty, and the recipe avoids adding extra salt elsewhere.

The onions also play a role in balance. Their sweetness (from caramelization and honey) and tang (from mustard) help round out the sandwich so the cured meat and sharp cheeses feel bold rather than harsh.

A French dip-inspired panini for hot sandwich fans

This is the kind of sandwich that’s best eaten hot, freshly pressed, and served with its dipping cup close by. It borrows the essential pleasure of a French dip—rich meat, melted cheese, and au jus—while leaning into the deli flavors of pastrami on rye. The beer-mustard onions tie everything together, adding a jammy layer that keeps each bite balanced even as the flavors stay unapologetically big.

If you like your sandwiches crisp on the outside, gooey in the middle, and designed for dipping, this French-ish dip panini is built to deliver exactly that.