Begin by heating the olive oil in a large ovenproof casserole dish over a medium heat. Add the onion, allowing it to soften and become caramelized, stirring occasionally to prevent it from browning too quickly. Once the onion is golden, add the garlic and sliced chilli, cooking for a couple of minutes.

Next, stir in the chilli powder, paprika, cumin, fennel seeds and oregano, allowing the spices to toast a little in the hot oil. Add the tomato paste, stirring it into the mixture until it begins to darken slightly.

Toss in the shiitake mushrooms, stirring them through the fiery mixture. Allow them to cook down slowly, absorbing all the flavours. They will release their moisture at first, but continue to cook them until the moisture evaporates and they start to brown.

When the shiitakes have caramelized, add the kidney beans (and liquid from the jar/can), bay leaf, cinnamon stick, salt and soy sauce. Stir it all together, making sure everything’s coated, then let the mixture simmer away gently for about 15 minutes over a low heat. Meanwhile, preheat your oven to 220°C/200°C fan (425°F/Gas Mark 7) and prepare the potato topping. Slice the potato to around 2mm (¹⁄₁₆ inch) thick, using a mandoline or a sharp knife.

Remove the bay leaf and cinnamon stick from the casserole dish, then arrange the sliced potato on top of the filling, overlapping each piece. Drizzle with a little olive oil, sprinkle with a little salt and transfer to the oven for 35 minutes or until the potatoes are crisp and golden brown. Scatter with sliced green chilli to serve, if you like.