Tip the pizza base mix into a bowl and make up according to the packet instructions. Roll out the dough on a lightly floured surface to a circle, about 25 cm (10 inches) in diameter, and place on a nonstick baking sheet.
Place the paste or pesto in a small bowl and add the chopped basil. Spread over the pizza base, leaving a 2.5 cm (1 inch) border around the edge. Arrange the tomato and mozzarella slices over the top and scatter over the capers in the gaps between. Season well.
Place in the top of a preheated oven, 220°C (425°F), Gas Mark 7, for 15–20 minutes until golden and cooked. Drizzle with oil and serve cut into wedges.