Preheat the oven to 180°C (350°F).
Heat a large lidded cast iron skillet or oven-proof pot over medium heat with the olive oil. Add the onions and carrot and cook with the lid on for 6 to 8 minutes until softened, stirring occasionally. The lid traps steam and prevents over-browning.
Add the garlic and fry for a further minute. Add the tomato paste, cumin, smoked paprika, Worcestershire sauce, mustard and chipotle. Stir to combine.
Pour in the blitzed tomatoes or passata. Add the brown sugar, maple syrup and drained beans. Season well with salt and pepper. Add extra chipotle or chilli flakes if you like more heat. Tuck the rosemary sprigs into the sauce and submerge them.
Put the lid on and bake in the oven for 30 to 40 minutes. You can stir once halfway through.
Remove the rosemary sprigs. Taste and adjust seasoning. Serve hot on toast with any accompaniments you like.