Custards: In a small saucepan, combine the cream with the Parmesan, salt and pepper; cook over medium heat until bubbles appear around inside edge of the pan.
Remove from the heat, cover and let sit for 30 minutes.
Preheat oven to 250 degrees F (120 degrees C) Pour the mixture into a measuring cup, add the egg and gently whisk.
Carefully pour the mixture into four 1-ounce ramekins.
Place ramekins in a roasting pan and pour enough boiling water into the pan to reach halfway up the sides of the cups.
Bake for 1 hour, or until set.
Remove from the oven and allow the custards to cool in pan with water bath for approximately 5 minutes.
Soup: Melt butter in a medium saucepan over medium heat.
Add leek and cook until softened, but not browned.
Add vegetable broth and fresh mint to the saucepan and increase the heat and bring to a boil.
Add the frozen peas and salt and pepper to taste.
Return to a boil, cover and reduce heat to a simmer until the peas are just tender, approximately 3-5 minutes.
Remove the mint and puree the soup in a blender or hand blender until smooth.
Stir in heavy cream and return to saucepan to heat again before serving.
Run a sharp knife around the insides of each ramekin and un-mold into the centre of each soup dish.
Carefully pour in warm soup and garnish with fresh mint if desired.