At least 24-48 hours before cooking, add 1 gallon of water and ¼ cup of salt to a bowl. Mix that together until the salt dissolves. Add your bone marrow to the mixture, cover and place in the fridge. Let sit in the fridge for at least 12 hours, but ideally 24-48 hours. Make sure to change out the water and remix the salt every 12 hours. Once done, pull out your bones and lay out on a tray. Season with salt and place in the fridge until ready to use.
Begin by slicing your picanha into steaks going from edge to edge instead of top to tail. Once sliced, carefully form them into a “C” shape and skewer them onto the skewers/sword. Once they are on the skewers, secure them with wire if needed. Lather in oil and generously season with the Coarse Sea Salt & Garlic Powder. Add more salt than you might think as the fat will render and you will lose some salt in the process of cooking.
Preheat your fire/charcoal for indirect cooking around 350F so that the picanha can “lean” against the heat.
Add your skewers so that they can lean against the fire and cook slowly. Cook for about 30-45 minutes until they are 120F internal for medium rare. Rotate them 2-3 times to prevent flare up and so they cook evenly. Make sure to cook off some of the fat layer if you desire too! Once the steaks are done, pull them off and let them rest for 15 minutes.
Next, pull your bone marrow out of the brine and pat dry. Generously season with kosher salt and place on a grill grate over the flames to cook at medium heat (about 325F). Cook for about 3-4 minutes per side or until the bone marrow is bubbling and caramelized. Once bone, pull off and scoop the bone marrow into a bowl. Mix in the other ingredients for the Bone Marrow Chimichurri excluding the olive oil. Mix together then slowly add the olive oil until it is to your desired consistency.
Slice your picanha either on the skewer or off. Top with the Bone Marrow Chimichurri and enjoy!