Seville orange paste is sold in Persian groceries. You can also make it at home. This recipe requires 20 Seville oranges, 45 minutes’ preparation time and 1 ½ hours’ cooking time, and produces 1 cup of paste.
- Remove the peel in a 1-inch-wide strip around the middle of each orange (this reduces the bitterness). Halve each orange and remove the seeds. Juice each orange, and strain the juice.
- Pour the juice into a non-reactive pot, bring it to a boil, reduce the heat to medium and simmer, uncovered, over medium heat for about 1 ½ hours. As the juice thickens, you will need to stir constantly, to prevent sticking and burning, When it has reduced to a thick, soft paste, remove it from the heat.
- Store the paste in a tightly closed jar in the refrigerator