Step 1

Heat the oven to 325ºF with a rack in the middle position. Lightly coat a 9-by-5-inch loaf pan with oil and flour. In a food processor, combine the white sugar and orange zest; process until the sugar is damp and fragrant, 5 to 10 seconds. Transfer to a large bowl.

Step 2

Add the pistachios to the processor and pulse until coarse, 8 to 10 pulses. Set aside 2 tablespoons of the nuts for topping. Add the flour, baking powder, cardamom and salt to the processor with the nuts. Process until the nuts are finely ground, about 45 seconds.

Step 3

To the sugar mixture, whisk in the eggs, ½ cup of yogurt, the oil, orange juice and vanilla. Add the nut-flour mixture and fold until mixed. Transfer the batter to the prepared pan and bake until golden brown, firm to the touch and a toothpick inserted at the center comes out with moist crumbs, 50 to 55 minutes. Cool in the pan on a wire rack for 15 minutes. Remove from pan and let cool completely, about 2 hours.

Step 4

In a bowl, whisk the remaining yogurt with the powdered sugar until thick and smooth. Spread over the cake. Sprinkle with the reserved nuts. Let set for 10 minutes before serving.