Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, sugar, baking soda, and salt, stirring with a whisk; add the vanilla bean. Store in an airtight container for at least 2 days. Remove bean, and reserve for another use.
Combine buttermilk and eggs in a large bowl, stirring with a whisk. Add flour mixture to buttermilk mixture, stirring with a whisk until well combined.
Heat a nonstick griddle or large nonstick skillet coated with cooking spray over medium heat. Spoon a scant 1/4 cup batter per pancake onto griddle. Turn pancakes when tops are covered with bubbles and edges look cooked (about 3 minutes).