Preheat oven to 350° and heat olive oil in a large kettle. Add onion, garlic, celery and salt. Sauté over medium heat for about 5 minutes. Add bell pepper and cook over medium low heat for about 10 minutes stirring occasionally. Add oregano and tomato sauce and simmer for about 15 minutes. In another large kettle bring about 6 quarts of water to boil. Add lasagna noodles and cook until the begin to soften. The noodles should still be somewhat tough because they will cook further while baking the lasagna. In a medium bowl mix the egg and the ricotta.
In a 9" x 13" baking pan spread 1/3 of the sauce on the bottom. Cover with 1/3 of the pine nuts and 1/3 of the spinach and basil leaves. Cover with three lasagna noodles. Then layer on 1/3 of the ricotta and egg mix and 1/3 of the mozzarella. Repeat layering until all ingredients are used (3 layers total). Cover with aluminum foil and bake for 30 minutes. Remove aluminum foil and bake another 15 minutes until cheese begins to brown.