- Cut the cabbage head into quarters and core the sections. Cut each section into fine, long shreds.
- Heat the oil in a wide, preferably cast-iron pan over medium-high heat. When the oil is hot, add the cumin, fennel, and sesame seeds. Once the sesame seeds begin to pop, put in the onion. Stir and fry for 3 to 4 minutes or until the onion has browned a bit.
- Put in the cabbage and leeks. Stir and fry for about 6 minutes or until the cabbage has browned somewhat. Add the salt. Turn down the heat to medium-low and cook, stirring now and then, for another 7 to 8 minutes or until the onions appear caramelized and soft. Note: you may need to do this in a couple batches.
- Add the lemon juice and stir.