Christmas Eve Truffle Mushroom and Steak Panini

Steps

1. 1

   Sear the filet mignon

   • Heat a 12-inch cast iron skillet or stainless steel pan over medium-high heat until very hot, about 2 minutes.
   • Pat the four filet steaks dry with paper towels and season generously on both sides with kosher salt and freshly ground black pepper.
   • Add 1 tablespoon (15 ml) of olive oil to the pan—it should shimmer immediately.
   • Lay the steaks in a single layer and sear for 3–4 minutes without moving them, until a golden crust forms.
   • Flip and sear the other side for 3–4 minutes for medium-rare (internal temperature of 130–135°F / 54–57°C), or adjust timing to your preference.
   • Transfer to a plate and let rest for 5 minutes before slicing thin.

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   Ready when: Golden brown crust on both sides; internal temperature 130–135°F (54–57°C) for medium-rare

   Tip: Don't move the steaks once they hit the pan—this locks in a crust. Let them rest off-heat so the meat stays tender.

2. 2

   Cook the porcini mushrooms

   • In a medium skillet over medium heat, warm the remaining ½ tablespoon (7.5 ml) of olive oil.
   • Add the sliced shallot and cook for 2 minutes, stirring occasionally, until softened.
   • Add the minced garlic and thyme, stir for about 30 seconds until fragrant.
   • Add the sliced porcini mushrooms and cook uncovered for 8–10 minutes, stirring occasionally, until they release their liquid and begin to brown at the edges.
   • The mushrooms should be tender and the pan liquid mostly evaporated.
   • Season with a pinch of salt and black pepper.
   • Remove from heat and let cool slightly, about 2 minutes.

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   Ready when: Mushrooms are tender and browning at edges; pan liquid is mostly evaporated

   Tip: Porcini mushrooms release water—let them simmer uncovered so the liquid cooks off and they develop deeper flavor.

3. 3

   Toast the ciabatta

   • Lightly toast each ciabatta piece (cut in half, so 8 slices total) on a panini press or griddle over medium heat for 1–2 minutes per side, just until they take on light color and become slightly crispy on the outside.
   • Don't over-toast—the bread will cook further when pressed.
   • Transfer to a cutting board and lightly brush the cut sides of 4 slices with softened butter.

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   Ready when: Bread is light golden and slightly crispy; still tender inside

   Tip: Light toasting adds crunch and helps the panini hold together when pressed. Over-toasting makes it dry.

4. 4

   Assemble the panini

   • Lay out the four buttered ciabatta pieces (butter-side down) on a clean work surface.
   • On each bottom slice, layer in this order: 1–2 slices of fontina cheese, one-quarter of the warm sautéed mushroom mixture, the thinly sliced filet mignon from one steak, a few arugula leaves if using, another slice or two of fontina to cap it off, then a drizzle of about ¼ teaspoon (1.25 ml) of black truffle oil.
   • Top with the second piece of ciabatta, buttered side up.

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   Tip: Assemble quickly so the warm mushrooms and steak keep the cheese ready to melt. Place arugula between cheese or mushroom layers so it doesn't wilt prematurely.

5. 5

   Press and grill the paniniOven 400°F / 205°C

   • Place each assembled panini on a preheated panini press or griddle (set to medium-high, about 400°F / 200°C).
   • If using a griddle or regular pan, weight the sandwich with a baking pan or cast iron skillet.
   • Cook for 3–4 minutes, watching for golden-brown marks to appear on the bottom.
   • Carefully flip or rotate using a spatula and cook the other side for 2–3 minutes, until the bread is golden-brown and the cheese is melted inside.
   • If the exterior is browning too quickly, lower heat to medium.

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   Ready when: Bread is golden-brown on both sides and fontina is visibly melted at the edges

   Tip: Panini presses vary—if you don't have one, a griddle plus a weighted cast iron skillet works perfectly. Don't rush: give the cheese time to melt fully.

6. 6

   Serve warm

   • Remove each panini from the press with a spatula and transfer to a warm plate.
   • Let rest for 1 minute so the interior settles slightly.
   • Serve immediately while the cheese is molten and bread is warm and crispy.

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   Ready when: Cheese is molten; bread is warm and crispy

   Tip: Serve right away—panini are best enjoyed at peak temperature and crispness.