Preheat oven to 425°F and lightly grease a baking sheet with cooking spray.
Wash and dry jalapenos, then cut in half, remove stems, and de-seed. Place on baking sheet with inside of pepper facing up spaced about 1 inch apart. Lightly spray with cooking oil and salt and pepper to taste. Flip over and lightly spray with cooking oil.
Bake for 16-19 minutes, until edges of jalapeno start to brown and skin starts to separate. Put in an air proof container (I prefer glass due to high temperature) and cover for 10-15 minutes if peeling off skins. This will help loosen the skins so they come off easily.
Once cooled, store in covered in the refrigerator. Enjoy!
Notes
For more heat, don't remove the seeds in the jalapeno.Proper spacing is important to make sure the peppers roast properly. If the sheet pan is crowded, the peppers will steam instead of roast.