1To Make The Dough: Sift the flour, baking powder, and salt together; set aside.
2Cream the butter with 3/4 cup of the brown sugar and the white sugar. Beat in the eggs, milk and vanilla. Mix at high speed for 2 minutes, then reduce speed and gradually blend in the flour mixture. Cover and refrigerate dough for at least 3 hours.
3To Make Raisin Filling: Grind the raisins. In a medium saucepan combine the ground raisins, 1 cup brown sugar, 1 cup water, salt and lemon juice. Bring to a boil, and simmer for 3 minutes.
4Combine the cornstarch and 2 tablespoons of the water and mix until smooth. Add to the raisin mixture and continue to simmer until thick. Remove from heat and let cool. Once cool, stir in the chopped nuts.
5Preheat Oven to 350 degrees F (175 degrees C). Lightly grease baking sheets.
6On a floured surface, roll out the chilled dough to 1/8 inch thick. Cut into 2 3/4 inch rounds. Place rounds on the prepared baking sheet. Place a heaping teaspoon of the raisin filling on the cookie round and top with another round. Crimp the edges closed.
7Bake at 350 degrees F (175 degrees C) for 8 minutes. Allow cookies to cool on sheet until just barely warm.