Wash the tomatoes, remove the stems and cut them in half. Hollow them out slightly and season the inside with salt and pepper. Stuff each tomato with 2 to 3 basil leaves, sprinkle with olive oil and top the tomatoes with half the pesto and pieces of mozzarella or burrata. Season with salt and pepper once again. Bake the tomatoes for about 10 min., regularly turning them on each side, allowing them to cook evenly. Once the cheese has melted, add the remaining pesto and basil, or be creative with other fillings for the tomatoes, e.g. ham, speck or smoked salmon.