Method
Prep:30min  ›  Cook:2hr  ›  Ready in:2hr30min 

1. Mince celery root, kohlrabi and onion in a food processor. Combine minced vegetables and crushed garlic in a large bowl and set aside.
2. Combine tomato passata, tomato paste, chopped tomatoes, bay leaves and anise seeds in a medium to large saucepan and place on low heat. Slowly mix in minced vegetables as the sauce is warming.
3. While the sauce is simmering, divide broccoli into small florets and chop the peppers. Set broccoli and peppers aside.
4. Before adding the broccoli and peppers, ensure that the acidity of the tomatoes has been reduced to only a hint. The bay leaves and anise should reduce most of the acidity without the need to add any sugar to the mix. Additional anise or salt at this stage will offset any remaining strong acidity.
5. Once acidity has been reduced, add the broccoli and peppers to the mix. Keep over low heat and allow to simmer for at least an hour, stirring occasionally.
6. Remove bay leaves and add salt, black pepper and herbs to taste.

Other ideas

I consider the first four steps and the associated ingredients to be the "essentials" of my recipe. They give the savoury, fine-textured base which I aim for. The later vegetables for the coarser texture can be substituted with others. I simply use broccoli and peppers as I find they work particularly well in the recipe.