Heat a non-stick frying pan over a medium heat and add the oil. Cook the onions with the lid on for 10 mins, stirring every now and again, until soft and caramelised. Stir in the balsamic vinegar. Season well.
Put the pizza base on a baking sheet. Spoon the caramelised onions over the base and top with slices of goats cheese.
Bake in the oven for 5-8 mins, until the goats cheese has melted and the base is crisp.
