This was inspired by a pizza - of all things - that I had in a small town on the east coast of Tasamina. The combination of ingredients was delicious on a pizza base, and just as good in these tartlets. A great starter for a dinner party. The quality of the pesto - whether homemade or store bought - will imapct the overall taste, so use the best you can get! The baby mozarella balls - bocconcini- are sometimes called cherry bocconcini - and work best for this recipe. Arrugula is also known as roquette - a slightly peppery leaf.