Mix the ketchup with the beer, cola, sugar, maple syrup, Strattu di pomodoro, mustard and vinegar and reduce it slightly. Add the Worcestershire sauce, garlic puree, onion and Tex mex and reduce until you have the right flavour. Season with salt and pepper, allow to cool and check the flavour again after half an hour. Working from the bottom, cut the heart out of the cabbage so that 2/3 of the beer can will fit into it. Pour out half the beer from the can and then put the cabbage over the can. Season with salt and pepper. Place the cabbage in a roasting tin, spread the barbecue sauce on it and put it on the barbecue to cook at 180 °C. Brush more barbecue sauce on the cabbage every quarter of an hour and check whether it is cooked after an hour.