Heat oil in a 6cm-deep, 24cm round (top) ovenproof frying pan over medium-high heat. Add onion, carrot and bacon. Cook, stirring, for 5 minutes or until onion is softened. Add garlic. Cook, stirring, for 1 minute or until fragrant. Add mince. Cook, breaking up with a wooden spoon, for 8 minutes or until browned.
Add wine. Simmer for 2 minutes. Stir in passata and oregano. Season with salt and pepper. Reduce heat to low. Simmer for 15 minutes or until sauce thickens.
Meanwhile, break spaghetti in half and cook following packet directions. Drain well. Transfer to a heatproof bowl. Add parmesan, cream and 3/4 of the ricotta. Season with salt and pepper. Toss well.
Preheat oven to 200C/180C fan-forced. Transfer 1/2 the bolognese sauce to a heatproof bowl. Using the back of a spoon, press remaining sauce in frying pan to level. Arrange 1/2 the spaghetti mixture over sauce. Spoon over remaining sauce, then top with remaining spaghetti mixture. Dollop remaining ricotta over the top. Spread gently to cover. Sprinkle with mozzarella.
Bake for 25 minutes or until cheese is golden and melted. Stand for 5 minutes. Sprinkle with oregano. Serve.
