1. Bring a large pot of water to the boil. Add pasta and cook for 10 minutes or until al dente. Reserve one cup of cooking liquid, drain pasta and set aside.
  2. Meanwhile, make the carbonara sauce. Whisk together the egg yolks, parmesan and 1 tablespoon oil in a bowl. Season with pepper and set aside.
  3. Heat remaining olive oil in a large frying pan over medium high heat. Add bacon and cook for 2-3 minutes or until golden brown and crispy. Remove from the pan and set aside.
  4. Add pumpkin to the same pan the bacon was cooked in. Cook for 4-5 minutes or until pumpkin is just tender. Add basil stems, garlic and spring onion and cook for a further minute. Remove the pan from the heat and stir through bacon, pasta, reserved pasta liquid, egg mixture, baby spinach and three quarters of the basil leaves.
  5. Divide pasta between serving bowls and garnish with remaining basil leaves.