1 1/2 cups graham cracker crumbs
3/4 cup finely chopped walnuts
3/4 cup brown sugar, firmly packed
1 teaspoon ground cinnamon
1/4 teaspoon ground cardamom
1/2 cup unsalted butter, melted
2 cups cake flour
1 cup granulated sugar
1 1/2 teaspoons baking powder
1/2 teaspoon salt
1/2 cup unsalted butter, at room temperature
1 1/2 teaspoons vanilla extract
1 cup milk
Preheat oven to 350. Butter and flour a 10" tube pan, a 9" springform pan or an 8" square pan. To make the streusel, in a medium bowl, combine the graham cracker crumbs, walnuts, brown sugar, cinnamon, cardamom and melted butter. Blend well and set aside. To make the cake, sift the flour, sugar, baking powder and salt into a large bowl. Add the butter, eggs, vanilla and milk.
Beat vigorously until smooth and quite thick, about 1 minute. Spread half of the batter into prepared pan and sprinkle with half the streusel mixture.
Spoon remaining batter over the streusel and top with remaining streusel. Bake until cake tests done, about 50 minutes. Cool about 20 minutes, then remove cake from pan.