Spinach Artichoke spread, Mozzarella, and Sun dried Tomato Chicken sandwiches

Mmmm.   This sandwich has a lot of components, but they all work.  It's the perfect sandwich for a lunch with someone special-  easy to prep in advance, but thoroughly impressive in a "yes, you're special" kind of way.  You can even grill the chicken in advance, but I like the temperature contrast with the spinach spread!

Adapted from Jeff Mauro


Chicken:
4 boneless skinless chicken breasts
1/2 cup Balsamic  vinegar

Spinach and Artichoke Spread:
5 ounces (1/2 a box) frozen chopped spinach, defrosted, drained
1/2 cup sour cream
2 tablespoons mayonnaise
1 clove garlic, grated
1 lemon, zested and juiced
Salt and freshly cracked black pepper
One 6-ounce jar marinated artichoke hearts, drained

Sandwich Build:
Fresh Focaccia, recipe follows
1/2 cup sun-dried tomatoes packed in oil, sliced into thin strips
1 pound ball fresh mozzarella, sliced into 1/4-inch slices
2 cups arugula
Directions

For the chicken: Marinate the chicken in the Balsamic for at least 30 minutes or up to 2 hours in the refrigerator.

Preheat a grill pan or grill over medium-high heat.

Let any excess marinade drip off the chicken, and then grill the chicken for 5 to 6 minutes per side until cooked through. Once cooked, let rest 5 to 10 minutes. Then slice thinly on the bias.

For the spinach and artichoke spread: Squeeze the drained spinach with a kitchen towel to dry it out. Place into a food processor with the sour cream, mayonnaise, garlic, lemon zest and juice. Puree until smooth. Taste for seasoning and add the artichokes. Pulse 2 to 3 times to leave the artichokes slightly chunky.

For the sandwich build: Cut the Fresh Focaccia in half into triangles.  Spread each half with Spinach Artichoke Spread. Then, on the bottom of the bread, sprinkle over the sliced sun-dried tomatoes, top with chicken slices, place a layer of mozzarella down and top with arugula. Place on the other half of bread.