Layers of silky milk chocolate and caramel puddings come together for a taste that's out of this world. Toffee bits give each spoonful just a hint of crunch.
In deep saucepan, stir sugar with 2 tbsp water; bring to boil. Reduce heat to medium and boil, without stirring, until amber colour, 4 to 6 minutes. Remove from heat. Averting face and holding pan at arm's length, whisk in cream and butter until smooth, about 1 minute.
Meanwhile, whisk together milk, cornstarch and salt; whisk into caramel mixture until smooth. Cook over medium heat, whisking frequently, until steaming.
In bowl, whisk egg yolk; drizzle in about 1 cup of the caramel mixture, whisking constantly. Whisk back into pan. Cook (do not boil) over medium heat, whisking constantly, until thickened, 4 to 6 minutes. Strain through fine sieve into clean bowl.
Milk Chocolate Pudding: In saucepan, whisk together milk, cornstarch, sugar, cocoa powder and salt; cook over medium heat just until steaming.
In bowl, whisk egg yolk; whisk in half of the hot milk mixture in slow steady stream. Gradually whisk back into pan. Whisk in cream and chocolate; cook over medium heat, whisking constantly, until bubbly and thickened, 4 to 6 minutes. Strain through fine sieve into clean bowl.
In small glass dessert dishes, alternately layer milk chocolate and caramel puddings, making 2 layers of chocolate and 1 of caramel. Place plastic wrap directly on surface.
Refrigerate until chilled, about 4 hours.
Make-ahead: Refrigerate for up to 24 hours.