Prosciutto and Fontina Panini with Basil Pesto

Ingredients

For the Sandwich:

¼ cup cider vinegar
2 tablespoons sugar
1/2 teaspoon salt
1 large shallot, thinly sliced
1 loaf ciabatta, sliced lengthwise
1/3 pound prosciutto (about 10 slices)
1/3 pound fontina, thinly sliced
Fresh spring greens

For the pesto:

2 garlic cloves
2 cups baby arugula
½ lemon, juiced
1/4 teaspoon Kosher salt
¼ cup olive oil

Make the pickled shallots: bring the cider, sugar, and salt to a boil in a small saucepan over a medium flame. Simmer for a minute, until the sugar has dissolved, then pour the hot liquid over the shallots in a small bowl or jar so they are fully submerged. Allow to sit for 20 minutes, then place in an airtight container until ready for use. This can be done up to a week before.

Make the pesto: in a small food processor, pulse the garlic, arugula, lemon juice, and salt to combine. Stream in olive oil and continue to blend until all the ingredients are finely chopped and the pesto is smooth and creamy. Taste for seasoning and add more salt if necessary.

Preheat the toaster oven: Place the two slices of bread crust side down on a baking sheet and toast in the oven for 3-5 minutes, until beginning to crisp but not totally browned. Slather the bottom half of bread evenly with pesto and arrange the cheese slices in a single layer. Return just this slice of bread to the oven and continue to toast until the cheese has melted, about 3-5 minutes.

Slather the other slice of bread with the remaining pesto and arrange the pickled shallots on top, followed by the prosciutto. Sandwich the halves together.

References
Prosciutto and Fontina Panini with Arugula Pesto