Put 30g of butter into a small saucepan and place over a high heat. Cook, swirling the pan occasionally, for two to three minutes, until nutty and deeply brown. Take off the heat, carefully add the chilli flakes, preserved lemon and lemon juice, and set aside.
For the beans, add the remaining 20g of butter to a large frying pan and place over a medium-high heat. When hot, add the onion and fry for about seven minutes, stirring occasionally, until starting to caramelise.
Lower the heat to medium, add the garlic, biber salçasi and cumin, and cook for one minute.
Add the cream, beans (including the liquid) and 60ml of water. Cook for about five minutes, until the liquid has thickened and lightly coats the beans.
Drizzle over the Urfa butter, add a pinch of flaked sea salt and serve straight from the pan.
