COOK IT.
Preheat your charcoal in the CUBE 360 to a medium high heat (you want the charcoal to be ash white). Prepare the steak by removing from fridge at least 20 mins prior to cooking to come to room temp. Season well with sea salt.
For the glaze, combine all ingredients in a small saucepan and cook over a medium heat until sticky and glossy. Set aside until ready to cook your steak.
Start off the grill cook with the mushrooms, cup side down, fill the gills with butter and garlic. Place the lid on the CUBE 360 and allow to cook for 3-5 mins. At this point, fan the coals and start cooking the steak to your liking. This will always vary depending on a number of factors: thickness of steak, temperature of steak, temperature of grill and of course, how you like your steak cooked. During the cooking process, using a pastry brush, brush the steaks generously with the rum glaze. Turn frequently and keep applying the glaze, ensuring not to let it burn. Once the steak is cooked to your liking, remove from heat along with the mushrooms and allow to rest. At this time you can baste further with the rum glaze. Once the steak has rested (generally half the time it took to cook), use a sharp knife and slice steak and mushrooms.
For the salad, at the last minute before serving, gently toss salad leaves with oil, lemon, salt and pepper.
Serve the steak alongside the mushrooms and a big side of salad.