Melt marg/butter & marshmallows in slow cooker on high, about 20-30 minutes, till all melted, (lid on) pour in rice bubbles mix through till marshmallows mix covers all rice bubbles. Pour into lined tray (I wet my hands & press it all down) decorate with whatever you like. (melted chocolate, mini choc bits, anything) put in fridge till set, then cut up to size you want.