Heat the olive oil in a large skillet over medium heat. This will help to sauté the vegetables and develop their flavors.

Add the chopped onion and sauté for about 5 minutes until translucent. Stir occasionally to prevent burning.

Add the minced garlic, diced carrot, and diced celery. Cook for another 5-7 minutes until the vegetables are softened.

Increase the heat to medium-high and add the ground beef. Break it apart with a wooden spoon and cook until browned, about 8-10 minutes. This step is crucial for developing a rich flavor.

Once the meat is browned, drain excess fat if necessary. Then, stir in the crushed tomatoes, tomato paste, beef broth, oregano, basil, and bay leaf.

Bring the mixture to a simmer, then reduce the heat to low. Cover and let it cook for at least 60 minutes, stirring occasionally. The longer it simmers, the deeper the flavors will become.

Season with salt and pepper to taste before serving.

In a large pot, bring salted water to a boil. The salt enhances the pasta's flavor.

Add the spaghetti and cook according to package instructions until al dente, usually about 8-10 minutes.

Once cooked, reserve a cup of pasta water, then drain the pasta in a colander.

Add the drained pasta to the Bolognese sauce and toss to combine. If the sauce is too thick, add a little reserved pasta water to reach the desired consistency.

Plate the pasta Bolognese and sprinkle with freshly grated Parmesan cheese. Garnish with fresh basil leaves if desired.

Serve immediately and enjoy your delicious homemade pasta Bolognese!