Preheat oven to 350°F. Spray a bundt pan with nonstick cooking spray (use the kind with flour for best results).
Whisk together flour, salt, and baking powder in a medium bowl. With an electric mixer, cream butter and sugar until light and fluffy. Add eggs, one at a time, beating well after each addition.
Combine buttermilk with orange zest, orange juice, vanilla extract and orange extract (if using) in a measuring cup.
Add the flour mixture (with the mixer on low) in three parts alternately with the buttermilk mixture, beginning and ending with flour. Beat just until it comes together. Do not overmix!
Pour batter into prepared pan. Bake until a toothpick inserted in centers comes out clean, 45-55 minutes.
While the cake is baking, make the glaze by heating granulated sugar and orange juice in a small pan over low heat. Bring to a simmer and stir. Once sugar is dissolved, remove from heat and let sit until cake is done. It will thicken as it cools.
Once done, cool cake 10 minutes in pan, then turn out cake onto a rack. Use a pastry brush to spread the glaze evenly over the tops and sides of the cake. Let dry and cool completely before drizzling with frosting.
Make the drizzle by whisking powdered sugar with juice and zest. Use 1-2 tablespoons of juice for desired consistency. Leave the cake on a rack. Drizzle over cake and let dry, about 30 minutes. Carefully transfer cake to a serving plate.
Store loosely covered for up to 3 days.