Preheat oven to 325 degrees. Butter and flour a 10-inch nonstick Bundt pan.
Mix flour, baking soda, ground ginger and salt in a medium bowl.
In a separate bowl, combine butter, sugar, and lemon zest and mix on medium-high speed until light, about 3 minutes.
Beat in eggs one at a time.
Add crystallized ginger (or additional ground ginger) and vanilla.
Reduce mixer to low. Add one third of flour mixture, then half of buttermilk. Repeat, ending with flour mixture.
Transfer batter to pan. Bake 60-70 minutes, or until a skewer inserted in cake comes out clean.
Let cool in pan on a cooling rack for 15 minutes. Invert onto rack to cool fully.