1. Pat the bavette dry with some kitchen paper. Drizzle with a little olive oil, season well with sea salt, then set aside. Peel the swede and slice into discs about 1cm thick. Like with the bavette, drizzle with a little olive oil, season well with sea salt, then set aside.
2. Place a heavy-based chargrill pan onto a medium-high heat. Leave to heat up.
3. For the bagna cauda, add the garlic to a small pan and cover with half the milk and 100ml of water. Place on a low heat and simmer for 10 mins. Drain the liquid (so you only have the garlic in the pan), then add the remaining milk. Simmer for another 10 mins and drain the liquid again.
Into another small pan, add the anchovies and extra-virgin olive oil. Heat over a medium-low heat until the anchovies completely break down. Stir occasionally. Once broken down, add in the cooked garlic and mash with a fork or spatula until combined with the anchovies. Now remove things from the heat and stir in the butter and lemon juice until fully combined. Set aside and keep warm next to the chargrill.
4. Now for the steak. Pat dry again, then carefully lay down each steak onto the hot chargrill. Leave to cook for a minute before flipping over and cooking for another minute. If your steaks are thin then this will be enough cooking time, if they're from the fatter end of the bavette then flip again - changing the direction of the meat if you’re fussed about the char lines - and cook for another minute before flipping again and cooking for a final minute.
When done, remove the steak and leave to rest on a cooling rack set over a tray. Keep the chargrill on the heat because…
5. Add the discs of swede to the chargrill and cook for a minute or two on each side until soft and tender. Remove from the grill and cut into wedges.
6. Now the steaks have rested, rub them really well with the sprig of rosemary. Slice and season with some freshly ground black pepper. Divide the bang càuda between warmed plates, lay the swede wedges in the centre and, finally, top with the bavette.