Preheat oven to 400 degrees. Combine flour, baking soda, salt, baking powder, poppy seeds and lemon rind.
In a large mixer bowl, beat sugar and butter until fluffy. Beat in eggs until smooth. Add buttermilk and vanilla. Mix well. Stir in flour mixture JUST until moistened. Fill paper cup-lined or greased muffin cups 3/4 full.
Bake 20 minutes, or until golden brown. Serve warm.
Makes 12 to 15 muffins.