01 -
Set your oven to 392°F (200°C). Wrap the sweet potatoes in foil and roast them for 70 minutes.
02 -
Mix the sugar, salt, and cornstarch in a saucepan while the potatoes are cooking. Add the milk and whisk until there're no lumps left. Heat on medium, stirring constantly, until the mixture thickens.
03 -
Crack the yolks into a small bowl and give them a light whisk. Slowly stir in roughly 1/4 cup of the hot milk mixture to temper the eggs. Then pour everything back into the saucepan.
04 -
Cook over medium heat for about 2 minutes until it thickens more. Remove the pan from the stove, toss in the butter and vanilla, and whisk until it's smooth.
05 -
Spoon the custard into a bowl, cover with plastic wrap pressed on the surface to stop a skin from forming, and let it cool to room temperature.
06 -
Once the sweet potatoes have cooled a bit (10 minutes), cut off their tops, scoop out about a third of the insides, and evenly fill them with the custard.
07 -
Sprinkle about a teaspoon of sugar over each filled potato. Use a torch to melt the sugar into a bubbling caramel layer. Let it harden before serving.