Make a cut with the heel of your knife across the chestnut. Only one cut is needed and not a cross-cut. *See Notes
Place cut chestnuts into a bowl and cover with water. Make sure the nuts are submerged. Leave the nuts to soak for at least 30 minutes.
Preheat your oven to 350° Fahrenheit/ 180° Celsius just before you intend to roast your nuts.
Take your chestnuts out of the water and pat them dry with a clean kitchen cloth.
Spread the nuts over a tray lined with parchment paper.
Roast your chestnuts at 350° Fahrenheit/ 180° Celsius for about 25 minutes or until they are cooked through. *See Notes
Allow your nuts to cool after they have been roasted and peel by removing the shell and the skin surrounding the chestnut.
Enjoy as a snack as is or use further in your food.
Video
Notes
We found that one cut across the chestnut is more than enough to roast the chestnuts. We used to cut in a cross but it's not required. Besides we found that cutting in a cross, makes the nuts to turn out more dry You can choose to just cut once or to cut in a cross.
Roasting time might vary. It depends on the size and quality of your chestnuts.