Preheat oven to 350°F (180°C).

For cake: In the bowl of a stand mixer fitted with the paddle attachment, beat butter, granulated sugar, orange zest, and saffron at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition. Beat in vanilla and orange blossom water.

In a medium bowl, whisk together flours, baking powder, cardamom, and salt. With mixer on low speed, add flour mixture to butter mixture in three additions alternately with yogurt, beginning and ending with flour mixture, beating just until combined after each addition.

Spray a 10-cup Bundt pan with baking spray with flour. Spoon batter into prepared pan, smoothing with an offset spatula. Firmly tap pan on a kitchen towel-lined counter several times to settle batter.

Bake until a wooden pick inserted near center comes out clean, 1 hour to 1 hour and 10 minutes, covering with foil halfway through baking to prevent excess browning. Let cool in pan for 15 minutes. Invert cake onto a wire rack, and let cool completely.

For glaze: In a medium bowl, whisk together confectioners’ sugar, 1 tablespoon (15 grams) water, and orange blossom water until smooth; pour onto cooled cake. Garnish with pistachios and candied orange, if desired. Store in an airtight container for up to 3 days.