Steam pumpkin until tender. Transfer to a bowl and mash with a fork.
Meanwhile, peel and finely chop onion. Heat 2 tablespoons oil in a frying pan and cook onion, over medium heat, stirring, for 3-4 minutes or until translucent. Transfer to the bowl.
In another bowl soak bread, town into small pieced, in water until just soft. Squeeze out excess water and add bread to the pumpkin and onion.
Add mince, egg, salt, pepper and crushed garlic. Using clean hands "knead" the mixture until it resembles sticky dough and all ingredients are well combined, for about 3 minutes.
Form rissoles using a large handful of the mince.
Heat about 2 tablespoons oil in a large frying pan over medium heat. Fry rissoles in batches for about 3 minutes on each side - turning gently, or until golden brown on the outside and cooked through on the inside - you can test one by cutting it in half.