Grease 4 ovenproof moulds (each containing approx. 200 ml). Cut the granadillas in half and put the flesh of 1/2 fruit in each mould. Caramelise 125 g sugar in a pot until golden. Add 3 tablespoons of hot water.
Boil the caramel with it while stirring and distribute it in the moulds. Let it set.
Place the ramekins in a flat casserole dish and place the dish on an oven rack. Mix eggs, egg yolk, 75 g sugar, milk and cream with a whisk. Pour through a fine sieve and distribute into the ramekins.
Heat the water and pour so much into the casserole dish that about 2/3 of the dish is in water. Place in the preheated oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2) and let it set for 45-50 minutes.
Allow the cream to cool, then cover and chill for 2-3 hours. Use a sharp knife to remove the cream from the rim of the mould, turn out onto plates and decorate with mint.