Step 1

Arrange a rack in middle of oven; preheat to 325°. Coat a 9x5x3" loaf pan with nonstick spray. Dust pan with flour; tap out excess.

Step 2

Whisk 2 cups flour, salt, and baking powder in a medium bowl. Using an electric mixer, beat butter on medium speed until light and fluffy, 2–3 minutes. Add sugar; beat until well incorporated, 1–2 minutes. Add eggs one at a time, beating to blend between additions. Add juices and zests; beat until well combined (mixture will look curdled), 2–3 minutes. Add dry ingredients; reduce speed to low and beat just until blended. Fold in ¾ cup pistachios. Pour batter into prepared pan; smooth top. Sprinkle remaining ¼ cup pistachios over.

Step 3

Bake cake, rotating halfway through, until a tester inserted into center comes out clean, about 1½ hours. Transfer to a wire rack and let cool completely in pan. Run a sharp knife around sides to loosen; unmold cake.

Step 4

Do Ahead: Cake can be made 1 day ahead. Store airtight at room temperature.