Antoni Porowski's Croque Signore
- 4 Tbsp 1/2 Stick of Unsalted Butter
- 1/4 Cup All-Purpose Flour
- 1 1/2 Cups Whole Milk
- 1 Tbsp Dijon Mustard
- 1/4 Tsp Kosher Salt
- Freshly Ground Black Pepper
- 8 1/2-Inch-Think Slices of Rustic Bread
- 6 Oz Thinly Sliced Mortadella
- 8 Oz Thinly Sliced Provolone Cheese
- 1/3 Cup Chopped Pepperoncini Plus more for serving
- 1/3 Cup Thinly Sliced Fresh Basil Leaves
- 1 Tsp Grated Lemon Zest
1. Heat the oven to 425. Line a baking sheet with parchment paper
2. Spread the nuts on a small baking sheet and bake until fragrant and lightly toasted, about 5 minutes. Let cool, then coarsely chop.
3. For the bechamel: Melt the butter in a medium saucepan over medium heat. Add the flour and cook, stirring, until foamy and pale, about 3 minutes. Add the milk ¼ cup at a time, stirring constantly, until combined and smooth. Then continue cooking, stirring occasionally, until the sauce is thickened, about 4 minutes. Remove from heat and whisk in the mustard, salt, and a generous grinding of pepper.
4. To assemble: Arrange the bread on a work surface and spread the slices evenly with the bechamel (about 3 tablespoons per slice). Arrange 4 of the slices on a prepared baking sheet., bechamel side up. Top with the mortadella. Continue building the sandwiches, using half of the cheese and all of the pepperoncini, pistachios, basil, if using, and lemon zest, then top with the remaining bread, bechamel side up. Top the sandwiches with the remaining cheese and season with pepper.
5. Bake the sandwiches until the tops are bubbling and golden, 12 to 15 minutes. Serve with extra pepperoncini alongside.