Chocolate Nutella Pudding

Chop 4 oz. chocolate; set aside. Whisk ¼ cup cornstarch, ¼ cup sugar, ¼ cup cocoa powder, and 1 tsp. kosher salt in a medium saucepan. Very slowly stream in 3 cups milk, whisking constantly, until lump-free.

Cook over medium heat, whisking constantly and vigorously, until pudding is bubbling and thick enough that wires of whisk leave a trail, 7–10 minutes.

Remove from heat. Whisk in one-quarter of the chopped chocolate until smooth. Add remaining chocolate in three additions, whisking after each addition, until chocolate is melted and mixture is smooth. Whisk in 1 tsp. vanilla.

Place 1 cup Nutella in a medium bowl and add about ½ cup warm pudding mixture. Whisk until smooth, then whisk in remaining pudding mixture until incorporated. Cover pudding with plastic, pressing directly onto surface to prevent a skin from forming. You can let it cool slightly at this point and serve warm, or chill pudding until completely set, at least 2 hours.

Meanwhile, crush ½ cup hazelnuts with the bottom of a small saucepan to break into irregular bits. Cook hazelnuts and 2 Tbsp. butter in saucepan over medium heat, stirring often, until butter is browned and hazelnuts are golden, 8–10 minutes. Let cool.

If serving pudding warm, divide among bowls or ramekins. (Or, you know, feel free to eat it right out of the pot.) If pudding is chilled, transfer to a large bowl and whisk until smooth before serving. Top with hazelnuts and a sprinkle of sea salt.

Do Ahead: Pudding can be made 3 days ahead. Cover, pressing plastic directly onto surface, and keep chilled.