Remove the lower rack from the halogen oven and place the pizza base on top.
Spread the pizza base with the onion relish. Scatter the tomatoes and mushrooms over the relish. Arrange the slices of goats' cheese on top. Sprinkle with salt and pepper, drizzle with 1 tablespoon of the oil and position the rack in the oven.
Set the temperature to 200°C (392°F) and cook the pizza for about 8 minutes until the cheese is melting. While cooking, blend the pesto with the remaining olive oil.
Drizzle the cooked pizza with the pesto mixture and scatter with rocket to garnish. Cut the pizza into slices and serve.