Bring a large pot of lightly salted water to the boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain. Toss with 2 tablespoons oil, then refrigerate for 1 hour or until cool.
Heat a non-stick pan over medium heat. Cook spinach until wilted. In a large bowl, combine spinach, green pepper, red pepper, yellow pepper and cooled pasta. Whisk together 125ml oil, walnut oil, vinegar and honey. Pour vinaigrette over pasta mixture and toss until evenly coated. Sprinkle top with Gorgonzola and chopped walnuts.