Preheat the oven to 400°F (200°C)
Rinse and dry the chestnuts
Place each chestnut flat-side down on a cutting board
Cut a deep X or slit through the shell on the rounded side
Arrange the chestnuts in a single layer on a baking sheet
Bake for 20 to 25 minutes
Shake the pan once halfway through baking
Remove the chestnuts when the shells open and the insides are tender
Wrap the hot chestnuts in a clean kitchen towel for 5 to 10 minutes
Peel off the shell and inner skin while still warm
Serve immediately