Heat the olive oil in a large pan over medium heat. Add the sliced onion and red pepper and cook for 5 minutes until softening.
Add the minced garlic, smoked paprika and chilli flakes. Stir and cook for 1 minute until fragrant.
Pour in the chopped tomatoes, drained butter beans and vegetable stock. Stir everything together.
Bring to a simmer and cook for 15 minutes until the sauce has thickened and the flavours have melded together. Season well with salt and pepper.
Serve in bowls with crusty bread for dipping, or over rice.