Put the pumpkin cubes in a flat baking dish and drizzle with a tablespoon of olive oil. Cook in the oven for 30 minutes.
Heat a tablespoon of olive oil and sauté the onion and carrot. Add rice and stir with the oil. Gradually pour in the stock and cook while stirring until all the liquid is absorbed.
Puree the pumpkin in a blender and stir into the risotto. Season to taste with oregano, thyme, salt and pepper.
Spread the risotto mixture about 3cm thick on a baking sheet and allow to cool, then cut out circular patties. Turn in semolina and fry in hot oil until crispy.