Begin by slicing your focaccia bread horizontally. A clean slice will make for easier assembly.
Using a spreader, generously apply the pesto to the cut sides of the focaccia.
Start layering the mortadella slices on one side of the focaccia, overlapping them slightly.
Gently tear open the burrata and place it on top of the mortadella.
Place the sliced tomatoes on top of the burrata, followed by a handful of fresh arugula. Season with salt and pepper.
Drizzle some balsamic cream over the arugula.
Place the top half of the focaccia back on and press down gently. Slice the sandwich into portions and serve immediately.