Dice or slice your onion to the size desired and sauté in olive oil until translucent. Meanwhile, dice your bell pepper and add it to the pan along with the chopped garlic and grated carrot. Add tomatoes and herbs, and simmer on low heat until sauce acquires desired thickness. Salt, pepper, and add a grating of nutmeg. Serve atop very hot al dente pasta, garnished with Parmesan and truffle slivers.