How to Make It
Heat 1 cup oil in a large saucepan over low. Add bell peppers, carrots, beets, and two-thirds of the sliced chiles. Cover and cook, stirring occasionally, until vegetables begin to steam, about 15 minutes. Increase heat to medium, and cook, covered, 30 minutes. Taste vegetable mixture to see if it is spicy enough; if necessary, add remaining one-third sliced chiles. Cover and cook until vegetables are very soft and starting to fall apart, about 45 minutes. Remove from heat.
Stir in tomato paste, garlic, fenugreek, salt, and coriander. Let cool 15 minutes. Transfer mixture to a food processor, and process until smooth, about 1 minute.
Spoon pureed mixture into a quart-size sterile glass jar with lid. Top with remaining 2 tablespoons grapeseed oil to prevent oxidation. Let cool to room temperature. Attach lid, and refrigerate up to 2 weeks.