1. Pre-heat the oven to 180ºC. Mix the pumpkin pieces with 2 tablespoons of the olive oil. Season and cook in the oven until soft (approx. 25-35 minutes). When cooked remove from the oven and crush the pumpkin using the back of a folk. Set aside to cool.
  2. Put the cooked pumpkin into a bowl and combine with the remaining ingredients. Divide the mixture into 6 equal amounts and mould into burgers shapes. Cover and refrigerate for at least 20 minutes.
  3. To cook, pre-heat the grill to maximum. Lightly brush the burgers with some olive oil then season them. Place the burgers on the grill and cook for 6-10 minutes until golden brown.
  4. Make the crushed avocado by combining all the ingredients together.
  5. To serve, cut open burger buns and spoon some chipotle mayonnaise on the bottom, top with some rocket leaves and then the burgers. Top with some crushed avocado and some more chipotle mayo, finally add the bun lid.