Combine the rub ingredients in a pestle and mortar and bash together. Ensure the steaks are dry before seasoning with salt and rubbing in the dry rub.
Set the steaks on a cooling rack and leave uncovered in the fridge for 4-6 hours.
Briefly toast the walnuts in Roccbox before popping into a bowl, grating over the garlic and covering with 3 Tbsp of the olive oil. Set to one side to infuse.
Allow the steaks to sit at room temperature for at least 30 minutes before cooking and ensuring Roccbox is up to full temperature, pre heat a pan with a lug of oil and cook the steaks for around 2 minutes on each side. Leave to rest.
Wipe out the pan and add the spring onions and cherry tomatoes before returning the pan to Roccbox to burn the ingredients – this should take about 6-8 minutes.
Add the remaining dressing ingredients to the walnuts, chop the burnt tomatoes and spring onions and chuck them in too. Season well.
Carve the bavettes against the grain before topping with the dressing.