How to Make It
Line a 6-quart slow cooker with a slow cooker liner, if desired. Combine vinegar, tomato paste, cumin, Aleppo, salt, black pepper, and ¾ cup water in cooker. Add beef, eggplants, bell peppers, and onion; stir to combine. Cover and cook until meat is very tender, 6 to 7 hours on low or 4 ½ to 5 hours on high. Serve stew over couscous, garnished with oregano.
Instant Pot variation:
Follow prep instructions above and lock lid in place. Turn steam-release handle to sealing position. Select Manual or Pressure Cook (depending on model) and set to high pressure for 30 minutes. Carefully turn steam-release handle to venting position and let steam fully escape (float valve will drop). Release lid and turn off cooker. Serve stew over couscous, garnished with oregano.
Let stew cool to room temperature. Transfer to sealable freezer-safe containers. Cover and freeze for up to 3 months. Thaw in microwave or overnight in refrigerator.