Coat the bottom of a large pot with olive oil and turn heat on medium to medium-high. Add onion and saute until beginning to turn translucent. Add salt and stir inches Add garlic, stir in and saute until fragrant and onions are totally translucent. Add basil, oregano, and pepper. Add shredded carrot, stir in and saute for about 30 seconds. Add can of crushed tomatoes and tomato paste. Stir in and let simmer for at least 20 minutes and tomato paste has dissolved into the sauce.
Spread about 1/4 cup sauce in the bottom of a 9x13 inch casserole dish. Lay three sheets of lasagna noodles on top of sauce in dish. Drop a large spoonful of ricotta on each and spread with fingers until each sheet has a fairly even coating. Sprinkle mozzarella over ricotta, then add a little bit of sauce over each sheet. Layer three more lasagna sheets in same direction as the previous layer and gently press down. Repeat until you lay down a fifth layer of noodles.
For the final layer top with remaining sauce and mozzarella then sprinkle with a little salt, basil, and parsley.
Cover with foil and bake at 375 degrees F for 50 minutes. If desired, take off foil and put back in oven for another 5 minutes to crisp the top of the lasagna.