In a medium saucepan, whisk together 1/2 cup granulated sugar, 1/2 cup cocoa powder, 1/4 cup cornstarch and a pinch of salt until evenly combined.

Slowly pour in 3 cups whole milk or canned full-fat coconut milk while whisking, stopping to break up any lumps until the mixture is completely smooth.

Place the pan over medium heat and whisk constantly until the mixture comes to a low boil and thickens to a pudding consistency, about 8–10 minutes (it should coat the back of a spoon).

Remove the pan from the heat and stir in 2 ounces semi-sweet or dark chocolate (chopped) and 3 teaspoons vanilla extract until the chocolate is fully melted and the pudding is smooth.

Spoon about 3/4 cup of the warm pudding into a separate bowl, cover it, and place it in the refrigerator to chill. Cover the remaining pudding and divide it evenly between 4–6 parfait glasses. Cover the glasses and chill both the glasses and the reserved pudding until cold (about 30 minutes).

While the pudding chills, pour 1 1/2 cups heavy whipping cream into a large mixing bowl. Using an electric mixer, beat the cream until soft peaks form.

Add 1 tablespoon powdered sugar and 2 teaspoons vanilla to the cream and continue whipping until medium-stiff peaks form. Do not overwhip.

Remove the reserved chilled 3/4 cup pudding from the fridge and gently fold it into the whipped cream until evenly combined (mixture will be light and chocolatey).

Divide the whipped-pudding mixture evenly among the parfait glasses, spooning it on top of the chilled pudding layer.

In a small bowl, mix 1/2 cup roasted peanuts (chopped), 1/4 cup roasted almonds (chopped), 1/2 cup mini marshmallows and 1/2 cup semi-sweet chocolate chips. Sprinkle this rocky-road mixture evenly over each parfait.

Cover the assembled parfaits and chill until ready to serve. To serve, optionally top each parfait with ice cream and a drizzle of melted chocolate or hot fudge.