1- If you don’t have a hand blender, simply transfer the mixture to a food processor or blender to get a smooth mix. Make sure to be careful as a hot mix in a close space creates pressure while being mix and might explode.
2- If you want to eat it in the near future (but not tomorrow), keep the dried oregano on top for baking day and cover with cling wrap to keep in the freezer for up to three months. The night before you intend to have the moussaka for dinner, thaw it overnight. You can thaw the entire moussaka or some portion in the refrigerator overnight. Once it is totally defrosted, remove the clear wrap, dust the dried oregano on top and cover with aluminium wrap. Proceed with the baking instructions from above.
*Make sure none of your ingredients have been frozen if you plan to freeze the moussaka, as it is not good for food or hygiene safety!