Pesto Chicken Sandwiches

I'm a big fan of repurposing leftovers, and Paul had a great idea this week, We had leftover grilled chicken breasts, that had been marinated in a little olive oil and herbs de provence. Paul suggested we make pesto chicken sandwiches with the leftover pieces. 

We threw together a quick pesto (basil leaves, some leftover chopped walnuts, olive oil, Parmesan cheese... I forgot garlic!) in the food processor. I think the pesto looks so dark because we used walnuts instead of pine nuts. which are lighter in color.
 

We served them on hoagie buns, with a smear of pesto, some melted mozzarella and tomato slices. Delicious! Easy to make and cheaper than going out for lunch on Sunday.