To prepare the cabbage, wash and cut the cabbage into four equal-sized wedges and remove the outer layer of leaves if wilted. Make a V-shaped cut in the bottom of the core on each wedge, but avoid removing too much as it will make the cabbage fall apart while cooking.
To make the accompanying sauce, slowly melt the butter in a small saucepan then add a drizzle of oil to prevent the butter from burning. Increase the heat and add the chopped anchovies, shallot, and a generous pinch of chilli flakes to the pan. Cook for one minute or so, until sizzling, then season with salt and finish with a squeeze of lemon juice. Set aside and reheat later, if need be.
Drizzle the cabbage wedges all over with a little cooking oil and season with salt and pepper.
If cooking on a BBQ, place the cabbage wedges on the BBQ, flat-side down, over high heat. Cook for 4-5 minutes on each side, resisting the temptation to keep moving them around. Once the two flat sides are generously charred and the cabbage wedges are fairly soft, remove from the BBQ and rest for a few minutes while reheating the sauce (if need be).
If cooking in a pan, heat a large, heavy-bottomed griddle pan or frying pan (ideally cast-iron) until screaming hot. Place the cabbage wedges in the pan, flat-side down, and cook over a high heat for 4-5 minutes on each side, resisting the temptation to keep moving them around. You can also place something heavy, such as a clean saucepan, on top of the cabbage wedges while cooking to weigh them down and char more evenly. Once the two flat sides are generously charred and the cabbage wedges are fairly soft, remove from the pan and rest for a few minutes while reheating the sauce (if need be).
Drizzle each cabbage wedge with a generous amount of the hot butter and eat while hot.