1 can diced tomatoes
People put all sorts of things into a bolognese so here are some I saw:
The version with mushrooms is really really good and definitely worth a try. The pictures I took for this post was when I made that version, but both are really good.
Don’t skip the part about sweating the vegetables because it helps them get tender. I also say to simmer for at least 30 minutes but when I do it I usually reduce it to where I want it then I simmer it with the lid on for at least an hour.
I 100% recommend using a food processor to shred the vegetables if you can.
You can add water ½ cup at a time if it is getting too dry for how you want it, and of course you can simmer with the lid on or off to help control how wet the sauce ends up.