Rinse the chestnuts and pat them dry. Using a sharp knife, cut an "X" on the flat side of each chestnut, about 1/2 inch long and deep enough to go through the outer shell.
Soak
Place the cut chestnuts in a bowl of cold water and let them soak for at least 30 minutes (or up to 1 hour). This helps them steam from the inside and makes them easier to peel.
Drain and Dry
Drain the chestnuts and pat them dry with a clean towel.
Roast
Preheat your oven to 425 degrees F (220 degrees C). Spread the chestnuts in a single layer on a baking sheet. Roast for 20-25 minutes, turning them halfway through, until the shells have opened and the insides are tender and golden.
Peel and Enjoy
Let the chestnuts cool for a few minutes (but not too long) and peel while still warm. Remove both the hard outer shell and the thin inner skin. Serve warm.
Notes
Tips for Success
Choose chestnuts that are firm, heavy, and shiny, without cracks or holes.
Soaking makes them easier to peel and helps prevent them from drying out while roasting.
Be sure to cut an X on the flat side - this allows steam to escape and keeps them from exploding.
Serve them warm and enjoy as a snack, appetizer, or alongside a cozy meal.