1. Position a rack in the center of the oven and preheat the oven to 325°F. Grease the inside of a 10-inch Bundt pan. Dust the pan with flour.

To Make the Cinnamon Swirl:

2. In a small bowl, whisk together the flour, brown sugar, cinnamon, and salt, breaking up any large lumps of brown sugar. Add the melted butter and stir until blended and crumbly.

To Make the Pound Cake:

3. Sift together the flours, baking powder, baking soda, salt, and cardamom into a medium bowl. Whisk to combine, and set aside.

4. In the bowl of an electric mixer, using the paddle attachment, beat the butter at medium speed until very creamy, about 2 minutes. Gradually add the sugar and beat at medium-high speed until well blended and light, about 4 minutes. At medium speed, add the eggs one at a time, beating well after each addition and scraping down the sides of the bowl as necessary. Beat in the vanilla extract and orange zest. At low speed, add the dry ingredients in three additions, alternating with the buttermilk in two additions and mixing just until combined.

5. Scrape half of the batter into the prepared pan and smooth it into an even layer. Sprinkle the streusel mixture evenly over the batter. Scrape the remaining batter on top and smooth it into an even layer.

6. Bake the cake for 65 to 75 minutes, until a cake tester inserted into the center comes out clean. Cool the cake in the pan on a wire rack for 15 minutes.

7. Invert the cake onto the rack and cool completely.

8. Dust the cake lightly with confectioners’ sugar right before sering.