2 Granny Smith apples, peeled, cored and diced
1/2 cup fresh lemon juice
2 tablespoons butter
6 tablespoons superfine sugar, divided
2 tablespoons Irish whiskey
5 egg yolks
1/2 teaspoon vanilla extract
1 cup whipping cream
1 cup milk
3 tablespoons granulated brown sugar
Preheat the oven to 350 degrees. Butter six 6-ounce ramekins.
Sprinkle the apples with the lemon juice to prevent discoloring. In a medium skillet over medium heat, melt the butter. Add the apples and 2 tablespoons of the superfine sugar and cook until the apples begin to soften, 2 to 3 minutes. Divide the apple mixture among the prepared ramekins.
In a medium bowl, whisk the eggs, the remaining 4 tablespoons superfine sugar and vanilla together. Add the milk and the cream and whisk until well blended. Pour over the apples. Set the ramekins in a large baking pan and add hot water to come halfway up the sides of the ramekins. Bake until the custard is set, about 45 minutes. Remove from oven and let cool in the baking pan for 15 minutes. Remove from the water bath, cover with plastic wrap and refrigerate until serving time.
To serve, preheat the broiler. Sprinkle the top of each custard with ½ tablespoon brown sugar and place under broiler until caramelized, 3 to 5 minutes.