To make the pizza dough, just place all the ingredients together in a food processor and blend together for a minute or 2 till you have a soft, pliable dough. Turn out on a floured work surface and into a ball. Place in an oiled bowl, cover with a clean tea towel and leave to rise for 30 minutes. Meanwhile, prepare the pumpkin puree by heating the olive oil in a pan. Add the garlic, chopped thyme and pumpkin and cook for 20 minutes to soften and cook the pumpkin. You may need to add 2-3 tablespoons of water half way during the cooking time. Season well with salt and pepper and remove off the heat. Puree the pumpkin with a hand blender, adding in a little more water if necessary. When the pizza dough is ready, knock back and roll out to a thin circle. Place onto your pizza pan and spread over the pumpkin puree. Arrange the mozzarella slices on top, followed by the caramelized onions. Allow to rise for another 15-20 minutes, then bake in a hot oven at 200`c, for 20-25 minutes. When ready to serve, sprinkle over the chopped walnuts and rucola leaves and drizzle over a little more olive oil.