Pulse garlic in your food processor.

Add walnuts and pulse again.

Now throw in the basil, cheese, salt, and pepper. Pulse with pouring oil from the chute to aid blending. Reserve some oil to top the pesto as needed.

Thinly slice the tomatoes and fresh mozzarella.

Place spinach, tomatoes, and cheese on a plate. Drizzle it with some olive oil, balsamic reduction, a pinch of salt, pepper, garlic powder, and dried Italian herbs.

Slightly warm up the bread if desired.

Spread pesto on slices of bread. Add in tomatoes followed by spinach and mozzarella cheese layer. Add another slice of bread on top and gently press the sandwich.

With a sharp knife cut it into four equal pieces. If desired, secure each piece with a toothpick or cocktail pick.