2large(or 4 medium) focaccia or ciabatta bunsor 1 baguette, or 8 mini-sized French rolls, pretzel buns, or similar soft, but sturdy buns for sliders
1cupbaby arugula
6ouncesBrie cheesecut into thin slices
½cupfig jam
Instructions
Remove the steak from the refrigerator and place it on a plate. With paper towels, pat both sides dry and season liberally with salt and pepper on both sides. Let it come to room temperature while you caramelize the onions.
For the Dijon onions, heat 1 tablespoon of oil in a large saute pan over medium-high heat. Add the sliced onions and 1/4 teaspoon of kosher salt. Cook until the onions begin to soften and brown, 5-8 minutes. Reduce the heat to low and let cook, stirring occasionally, until the onions are very soft and caramelized, about 15 additional minutes.
Remove from heat and stir in the Dijon mustard to evenly coat the onions. Remove the onions to a plate or bowl, then with a paper towel, carefully wipe the skillet clean.
Preheat the oven to 350°F. Heat the remaining 1 1/2 tablespoons olive oil in the skillet over medium-high heat. Once the oil is very hot and almost smoking, add the seasoned steak. Sear the for 1 minute on each side, then reduce the heat to low and cook the steak for about 7 to 10 minutes, turning once, until very rare in the center and an instant-read thermometer inserted in the center reaches 125°F.
Transfer to a plate and cover with foil. Let rest for 10 minutes, then slice against the grain into strips.
To assemble the sandwiches, spread some of the melted butter onto the bottom of a 9x13-inch baking dish, using just enough to coat the pan. Lay the bottom of the buns in a single layer in the baking dish (if using a baguette, split it lengthwise into a top and bottom half, then cut it in half crosswise so you have two shorter sandwiches that fit in your baking dish).
Top the bread with the arugula.
Layer on the steak.
Add some slices of creamy brie.
Finish with the Dijon red onions.
Spread the inside of the top buns with jam, then lay the buns on top to complete the sandwiches. Brush the bun tops with the remaining melted butter, then cover the pan with foil.
Bake for 15 minutes, just until the cheese has melted. Transfer to a serving plate and enjoy warm.
Notes
*INGREDIENTNOTE: Feel free to substitute the strip steaks for another cut of beef you enjoy. Ribeye is a great option, though its texture isn’t as consistent throughout, so some pieces will be more marbled than others. For those who enjoy leaner steak, sliced tenderloin would be fantastic.
TO MAKE AHEAD: The Dijon onion topping can be prepared and stored in the refrigerator up to 2 days in advance. Whole sandwiches can be assembled, arranged in the pan, and kept at room temperature for 1 hour in advance. Bake just before serving.
TO STORE: Refrigerate leftover sandwiches in an airtight container for up to 2 days.
TO REHEAT: Gently rewarm sandwiches in a baking dish in the oven at 350°F.