Fillet of Beef with Turnip Tops. Bottarga Butter and Red Wine Sauce

Cime di rapa (also called turnip tops or broccoli rabe) is a dark, leafy green vegetable; if unavailable, use chicory, cavolo nero or English spinach. This is an interesting dish because it combines bottarga with meat; ask your butcher to trim the beef fillet of the surface connective tissue called silverskin and most excess fat. This bottarga butter is also great melted over any seafood or tossed through pasta – it keeps well in the freezer and adds a Sardinian flavour to almost anything,