Spoon marmite into a mug - about two thirds of a teaspoon will be sufficient. You can vary how much marmite you use depending on how much you can handle. Boil water in a kettle. Enough water to fill the mug. Pour the boiling water into the mug. Stir the mixture until it becomes a light brown colour throughout. Wait for the broth to cool before drinking If you wish, dip buttered bread into your broth to turn it into a meal. Insert all the ingredients into a mixing glass and add ice. Stir very well. Strain the mixture into a 12oz Collins (without ice). Garnish the cocktail with a celery stick and lemon wedge.