Step 1: Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan or line it with parchment paper.
Step 2: In a medium bowl, whisk together the flour, baking powder, baking soda, ground cardamom, and salt until well combined.
Step 3: In a large mixing bowl, cream the softened butter and granulated sugar together for 3-5 minutes until light and fluffy.
Step 4: Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract and fresh orange zest.
Step 5: Alternately add the dry ingredients and the Greek yogurt to the butter mixture, starting and ending with the dry ingredients. Stir until just combined.
Step 6: Pour the batter into the prepared pan. In a small bowl, mix the chopped pistachios with brown sugar and sprinkle evenly over the top of the cake.
Step 7: Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack.