Roast Rump Cap with Sauce Verte

Rump cap (picanha) is a cut I keep coming back to for big group cooks. It has a thick fat cap on one side that renders during the low-and-slow cook and bastes the meat from above, giving you deep flavour without a lot of hands-on work. This recipe uses a kombu-based seasoning from the team at Fallow restaurant in London, applied the night before so it has time to work into the surface. Sauce verte is the French take on green sauce: fresh herbs, mustard, creme fraiche and olive oil, blended smooth. It’s sharp, herby and rich, and it cuts through the fat of the beef well. The whole thing takes two minutes in a blender. The rest of the recipe is designed to be prepped ahead. The seasoning goes on the night before, the pre-cook can be done up to 5 hours before serving, and the beef holds its temperature in a good esky for the full window. That makes this viable for a Christmas lunch where you need the BBQ free for other things, as the final sear is only about 6 to 8 minutes.Ingredient NotesRump cap (picanha): The rump cap is the thick triangular muscle that sits at the top of the rump, covered on one side by a thick fat cap. That fat is the defining feature of the cut: it renders during the cook, bastes the meat and is the main source of flavour. Ask your butcher for a whole rump cap or picanha. If you can’t find it, tri-tip is the closest alternative in terms of shape and cook method. Top sirloin works but won’t have the same fat coverage. For a budget version, bolar blade roast is a reasonable substitute, though it needs a longer cook and different handling.Kombu: Kombu is dried Japanese sea kelp and one of the primary natural sources of glutamates, the compounds responsible for savoury, umami flavour. For this seasoning blend it’s toasted and ground, which transforms the marine quality into a deeper, more savoury note that reads as complexity rather than seafood. You’ll find dried kombu sheets at Asian grocery stores and specialty food shops. Toast a sheet in a dry pan over medium heat until fragrant and slightly crisped, then blitz in a spice grinder or high-powered blender until fine. If you can’t source it, omit it and increase the other spices slightly, or use your favourite steak seasoning blend instead.Creme fraiche: Creme fraiche is a cultured cream with a slightly tangy, sour flavour and a thick, stable consistency. In the sauce verte it adds richness and acts as a partial emulsifier alongside the olive oil, giving the sauce a creamier body than a straight herb oil. It holds up well in the blender without splitting. You’ll find it in the dairy section of most supermarkets. Full-fat sour cream is a good substitute if you can’t find it. Don’t use regular pouring cream as it won’t give you the right consistency or acidity.EquipmentChopping boardChef’s knifeSmall bowlWire rack over trayHooded BBQ or ovenMeat probe or instant-read thermometerEsky or insulated boxBlender or food processorTongs