In a 3 quart saucepan, combine the ground poppy seeds, water and milk. Bring to a gentle boil and allow to simmer a couple of minutes. Add butter, honey, lemon zest, raisins, sugar, salt, cinnamon and stir well, reducing heat so that mixture cooks but does not burn or stick. The resultant mixture should be a paste. This should take 10-15 minutes.
Low heat is best.
Cool very well before using - filling will further thicken once cold. Keep filling refrigerated until needed. You can loosen filling with a touch of warm water.