- Combine the courgettes, aubergines, pumpkin, onion, and kohlrabi in a large pot or pressure cooker. Add the vegetable stock and 1 tablespoon of olive oil. Bring to pressure and cook for 8–10 minutes, or simmer for 1 hour. Cool, then purée the whole thing.
- Place a large handful of basil leaves and about 6 cloves of garlic in a mortar and pound until roughly crushed and a gritty paste is achieved. Add to the pot, stir and season to taste.
- Meanwhile, boil the beans separately until soft, then add to purée mixture.
- Boil the pasta until al dente then add to mixture.
- Serve with grated Parmesan or hard Edam sprinkled over it.
- Dried kidney beans will cause nausea, vomiting and diarrhea unless they have been boiled briskly (a slow cooker is not sufficient) for at least 20 minutes to destroy the very indigestible phytohaemagglutinin that they contain. They will then need another 60–90 minutes at a slow simmer to be tender. Tinned kidney beans are quite safe and do not need pre-cooking as their preparation involves sufficient heat to destroy the toxin.