Slice the peppers in half and remove the stems and seeds.
Place the peppers onto a grill-safe baking sheet that's covered in non-stick foil or parchment.
Place into the grill and let cook for 20-25 minutes. Flip halfway through the cook time.
Remove from the grill and place into a large bowl and cover in plastic wrap. A paper bag also works. Roll it shut to seal. You're trying to steam the peppers.
Let the peppers steam for 10-15 minutes.
Remove from the container and peel off the skin and discard.
Store in an air-tight container in the fridge until ready to use.