Put the sesame seeds in a small skillet/frying pan and place over a medium heat. Warm the seeds to lightly toast them on both sides. Remove from the heat and allow to cool.
Mix together the toasted sesame, sumac, oregano, thyme, marjoram and salt. Store in an airtight container until needed. Be sure to stir carefully before using as the sumac can tend to settle to the bottom and herbs to the top.
Notes
The recipe makes a little over 4tbsp of the spice blend - how many actual servings depends on how you use it, so nutrition is based on 4 servings.