Walnut-Arugula Pesto And Fresh Mozzarella Open-Face With Balsamic Syrup

Let's Cook

1. Step 1.

   Preheat the oven to 325°F. Spread the walnuts in a pie plate or small baking dish and toast for 12–15 minutes, until fragrant. Let cool completely.

2. Step 2.

   While the walnuts cool, make the balsamic syrup: In a small pan over medium heat, combine the balsamic vinegar and brown sugar or honey. Stir and bring to a soft simmer. Reduce the heat to maintain a low, constant simmer and cook, stirring often, until the liquid is reduced by half, about 10 minutes. Remove from heat and pour into a Pyrex measuring cup; it will thicken as it cools. Set aside.

3. Step 3.

   In a food processor, pulse the cooled walnuts, baby arugula, and garlic until finely chopped. Add lemon zest, lemon juice, salt, and sugar; pulse a few times to combine. With the machine running, add the olive oil in a slow, steady stream and process until smooth. Taste and adjust salt, sugar, or lemon juice as desired. Transfer the pesto to a small jar and refrigerate (or freeze for longer storage).

4. Step 4.

   Bisect each focaccia rectangle through the middle horizontally to create eight pieces. Lightly toast the bread in a toaster or under the oven broiler (about 1½ minutes under the broiler).

5. Step 5.

   Spread each toasted bread square with about 1 teaspoon (or more) of the walnut-arugula pesto. Place a thin slice (about ¼ inch thick) of fresh mozzarella on top of the pesto. Drizzle each sandwich with balsamic syrup. Serve immediately.