Preheat the oven to 200°C/400°F/gas mark 6. Put the whole, unpeeled onions in a roasting pan and cook in the centre of the oven for 45 minutes. Leave until cool enough to handle, then, using a sharp knife, cut off the tops and bottoms of the onions and peel off the hard skin. Cut the onions in half crossways and remove the inner layers, leaving just the outer shells. Arrange the half onion shells like cups in a shallow ovenproof dish. Chop the insides of the onions into small pieces. Peel the garlic and chop finely. Slice the sun-dried tomatoes into small pieces.
Heat the olive oil in a frying pan over a medium heat. Add the chopped onion, garlic, sun-dried tomatoes, pine kernels and oregano. Stir around over the heat for 4-5 minutes, then season with salt and plenty of freshly ground black pepper and spoon into the onion cups. Smear the outside of the onions with olive oil and a very little caster sugar.
Preheat the oven to 230°C/450°F/gas mark 8. Slice the goat’s cheese into 6 rounds and place a piece on top of each stuffed half onion. Sprinkle with black pepper and bake just above the centre shelf of the oven for about 20 minutes, until the cheese is bubbling and browned.