Season veal shanks all over with salt and pepper. Coat in rice flour; shake off excess. Heat oil in large, straight-sided skillet set over medium-high heat; cook shanks for 3 to 5 minutes per side or until golden brown. Transfer to plate.
Reduce heat to medium; add onion, carrots, celery, garlic, rosemary and thyme to skillet. Cook for about 10 minutes or until tender and fragrant. Stir in tomato paste; cook for 2 minutes or until deep red.
Stir in wine, scraping up browned bits; simmer for 2 to 3 minutes or until reduced by half. Stir in tomatoes and broth; bring to boil. Return shanks and any juices to skillet.
Cook, covered, on medium-low heat, for about 1 1/2 hours or until meat is falling off the bone. Remove shanks from skillet. Use a fork to shred meat; discard bones. Simmer sauce for about 20 minutes or until thickened. Stir in shredded meat and parsley. Let cool slightly.
Meanwhile, melt butter in saucepan set over medium heat. Stir in rice flour; cook for about 2 minutes or until bubbling. Whisk in whipping cream, a splash at a time, until smooth. Stir in salt and pepper. Cook, stirring constantly, for 5 to 7 minutes or until thickened; remove from heat and stir in saffron.
Preheat oven to 350°F (180°C). Grease baking dish. Ladle 1/4 of the veal mixture into bottom of dish. Top with 1/3 of the lasagne noodles, breaking noodles to fit snuggly. Top with 1/4 of the veal mixture, 1/3 of the buffalo mozzarella and 1/4 of the shredded mozzarella. Repeat layers twice. Pour cream sauce over top. Sprinkle with remaining shredded mozzarella, Parmesan, parsley and lemon zest.
Cover with foil; bake for 30 minutes. Remove foil; bake for about 15 minutes or until noodles are tender and sauce is bubbling. Let stand for 10 minutes before serving.
The osso buco sauce can be made up to 3 days in advance, then warmed gently before layering in the lasagne the day of serving.Serve with a good-quality Chianti for a truly authentic Italian experience.