Step 1

Make arugula pesto if using: Place everything in a food processor and pulse repeatedly, until uniformly combined, but not too smooth.

Step 2

Slice baguette in half lengthwise, leaving one side intact. Toast it a little if you like.

Step 3

Mix the 1/4 cup mayo and 3-4 tablespoons pesto together. Slather over the insides of the baguette.

Step 4

Layer with mozzarella and tomatoes. Season with salt and pepper.

Step 5

Add the fresh basil. Drizzle with olive oil and balsamic.

Step 6

Close the baguette and cut it into 5- 6 pieces. Tightly wrap any leftovers and keep in the fridge for up to 2-3 days.