Peel and finely chop the onion and peel and crush (mince) the garlic clove. Melt the butter in a pan, add the onion and garlic and fry gently for about 5-6 minutes until the onions are soft.
Meanwhile, beat together the eggs, milk, tomato ketchup and mustard (If traditionally hot English Mustard is not available, choose the hottest alternative mustard you can find). Then add salt and freshly-ground pepper to taste. Pour this into the pan with the onions and garlic and cook over a low heat, stirring gently until the mixture is set but still soft.
Heat the baked beans and arrange in a circle on a hot serving plate. Pile the scrambled egg in the centre and serve immediately.