For the budino: Combine cream and milk and set aside. In a large bowl, whisk together the eggs and cornstarch and set aside. In a medium saucepan, stir together the brown sugar, salt and water. Bring to a boil and cook until the mixture caramelizes, nutty and deep brown. Immediately whisk in the cream mixture. The mix will steam and the caramel will seize. Bring back to a simmer and stir until the mixture is smooth. After it returns to a simmer, temper into the egg mixture. Return to the saucepan and cook stirring constantly until the custard is very thick, about 2 minutes. Whisk in the butter and rum. Pass the mixture through a wire strainer, pressing to extract as much as possible. Divide evenly into 12 six-ounce glasses. Cover and chill.
For the topping: Combine the sugar, water and syrup in a saucepan. Heat to 325°. Remove from heat and stir in the cream and butter. Whisk until smooth. You may need to return to the heat to smooth lumps. Remove from heat and allow to cool. Whisk in the rum.
To serve: Drizzle warm prepared caramel sauce over the top of the chilled budino. Sprinkle a pinch of Maldon sea salt over the caramel and top with whipped cream.
Courtesy of Chef Mark Fischer, Six89