Preheat oven to 325°F.
Lightly grease an 8" springform pan with butter or coat lightly with vegetable cooking spray. Line the bottom of the pan with a piece of parchment paper, cut to fit, and butter or spray the parchment. Set aside.
In a medium mixing bowl sift together the flour, baking powder, baking soda and salt.
Add the butter and granulated sugar to the bowl of a stand mixer. Beat until the mixture is light and fluffy, about 5 minutes. Scrape down the sides and bottom and blend again. Add the vanilla bean paste and almond extract. Blend until incorporated.
Add the eggs one at a time, beating just until the yolk disappears.
With the mixer running on low and add the buttermilk and lemon zest blending just until combined. The mixture may look curdled at this point but that is normal.
Add the flour mixture in three batches mixing well after each addition. Don't over-beat however.
Spread the batter evenly in the prepared cake pan and sprinkle with 1 teaspoon turbinado sugar.
Bake for 35-40 minutes or until a wooden toothpick inserted in the center comes out clean. Cool the cake in the pan for 20 minutes, then remove the sides and bottom of the springform pan. Discard the parchment paper from the bottom and cool the cake completely on a wire rack before filling.