Preheat oven to 350 degrees F. Line a cookie sheet with parchment paper.
In a medium mixing bowl, cream together softened butter and sugar with a hand or stand mixer until light and fluffy. Careful not to overmix. Stir in the vanilla until combined.
In a small bowl, combine all-purpose flour, baking powder and salt. Add to butter and sugar mixture just ½ cup at a time, beating until combined.
Use a teaspoon measure to evenly portion cookie two teaspoon sized portions of dough onto the parchment lined baking sheet (it's okay if it's not exactly 2 teaspoons). Roll each dough piece into a ball. Space cookies two inches apart. Bake on the middle oven rack until edges are golden brown, 11-13 minutes. Yields 2 dozen cookies. They will firm up a lot as they sit.
Store in a closed container for 3-4 days at room temperature or freeze for up to 3 months.
Notes
Vegan butter: I've made this recipe with both Earth Balance buttery spread and baking sticks. Make sure that the butter is 100% room temperature. Slice it up into 3-4 pieces to allow it to come to room temperature more quickly. It is ready when you can make an indent with your finger without much resistance.
Flour: To evenly measure flour, spoon flour into a measuring cup. Level off excess flour with the back of a knife.
Sizes: This recipe is written for a little bit bigger cookies than classic nilla wafers. If you want cookies the size of actual vanilla wafers you only need to scoop out a rounded teaspoon. Bake for 10-12 minutes at 350F. For softer and more traditional sugar cookies, bake 1 tablespoon of dough for 9-11 minutes.