Tip:Note: Be sure to bake these cookies on a cookie sheet, not a rimmed baking sheet; otherwise, the dough will spread too much, and the cookies won’t retain a nice, round shape.
Position a rack in the center of the oven and heat the oven to 350°F. In a medium bowl, whisk the flour, baking powder, and salt to blend. Using a stand mixer with the paddle attachhment or a hand-held mixer, beat the butter and sugar on medium speed until light and fluffy, about 3 min. Scrape the bowl with a rubber spatula. Beat in the egg and vanilla until thoroughly combined, about 2 min. Scrape the bowl again. With the mixer on low speed, slowly blend in the flour until incorporated, about 30 seconds.
Drop the dough by rounded tablespoonfuls into a bowl of granulated sugar and roll to coat; then set the coated balls about 3 inches apart on ungreased cookie sheets.
Bake until the cookies are golden brown on the edges and slightly soft in the center, 15 to 18 min. Let the cookies cool on the sheet for 1 min. before transferring them to a rack to cool.
The cookies can be stored in an airtight container for up to three days.
Photo: Scott Phillips