Brush the outside of each slice of bread with oil, spread the pesto on the inside, place the mozzarella on the pesto on of one slice of bread, top with the tomato, season with salt and pepper and finally top the other slice of bread pesto side in.
Grill in a pan, preheated over medium heat, until golden brown on both sides and the cheese has melted, about 2-4 minutes per side.
