Sure! Here's a spaghetti recipe with onion, red bell pepper, eggplant, tomato sauce, carrot, and meatballs in metric units:

Ingredients:

- 400g spaghetti

- 1 onion, chopped

- 1 red bell pepper, chopped

- 1 eggplant, chopped

- 2 cups tomato sauce (500ml)

- 1 carrot, chopped

- 400g ground beef

- Salt and pepper

- Olive oil

Instructions:

1. Bring a large pot of salted water to a boil. Add spaghetti and cook according to package instructions until al dente.

2. While spaghetti is cooking, prepare the sauce. Heat olive oil in a large pan over medium-high heat. Add onion, red bell pepper, eggplant, and carrot. Sauté until vegetables are softened, about 10 minutes.

3. Add tomato sauce and stir to combine. Reduce heat to medium-low and let simmer for 15-20 minutes.

4. While the sauce is simmering, prepare the meatballs. In a bowl, mix ground beef with salt and pepper to taste. Form into small balls, about 1-2cm each.

5. Heat olive oil in a separate pan over medium-high heat. Add meatballs and cook until browned on all sides, about 10 minutes.

6. Add meatballs to the tomato sauce and let simmer for an additional 10 minutes.

7. Serve spaghetti with meatballs and sauce on top. Enjoy!

Makes 4 servings.