Preheat the oven to 375 degrees Fahrenheit and line baking sheets with parchment paper.

In a large bowl, cream together softened butter and granulated sugar with an electric mixer on medium speed for 2 to 3 minutes until light and fluffy.

Add the egg and vanilla extract and beat on medium speed for about 1 minute until fully combined and smooth, scraping down the bowl as needed.

In a separate bowl, whisk together all-purpose flour, salt, and baking powder until evenly mixed.

Gently fold the dry ingredients into the wet mixture with a spatula or wooden spoon until just combined, avoiding overmixing.

Use a small cookie scoop or teaspoon to drop portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Flatten each dough portion to about 1/8 inch thickness using the bottom of a water-dipped glass or the back of a spoon.

Bake for 10 to 12 minutes, or until edges are light golden brown and centers begin to color, watching closely to prevent overbaking.

Allow wafers to cool on the parchment paper for 2 to 3 minutes, then transfer to a cooling rack and cool completely, about 15 minutes.