Arrange rack in middle of oven. Preheat oven to 350°F. Using a pastry brush, butter a 12-cup Bundt pan; dust with flour, tapping out any excess.
In a food processor, pulse 1 cup pistachios until finely ground. In a medium bowl, whisk ground pistachios, flour, salt, baking powder, baking soda and cardamom.
With an electric mixer, beat butter and granulated sugar on medium-high until light and fluffy, about 3 minutes, scraping down sides of bowl as needed. Add eggs, 1 at a time, beating well after each addition. Reduce speed to low; add flour mixture in 2 batches, alternating with buttermilk.
Pour batter into prepared pan. Bake 45–50 minutes or until cake springs back to touch and a cake tester inserted comes out clean. Transfer pan to a wire rack set over a baking sheet or a piece of parchment paper; cool 30 minutes. Turn out cake onto rack; cool completely.