Step 1 Using a spice grinder, grind the poppyseeds into fine meal but not to a paste. This will need to be done in batches.
Step 2 In a small saucepan, combine the poppyseeds, milk, honey and 2 tablespoons sugar. Stir over low heat and bring to a simmer. Cook over low heat, stirring often, until the mixture is about as thick as peanut butter, about 10 minutes.
Step 3Add the raisins and butter, and stir over low heat just until the butter is blended in. Remove from heat and stir in the orange zest. Taste, and stir in the remaining 1 tablespoon sugar if you like.
Step 4Transfer the mixture to a bowl and set aside to cool to room temperature. Cover and refrigerate it until cold before using, at least 1 hour. This makes about 1 cup filling, enough for about 3 dozen hamantaschen.