Prep: Preheat oven to 325°F. Line two large baking sheets with parchment paper.

Chop pecans: Roughly chop 1 cup pecans using a sharp knife or pulse 4-5 times in a food processor. Leave some larger pieces for texture. Set aside 24 pecan halves for topping.

Cream butter and sugar: In a large mixing bowl, beat softened butter and brown sugar with an electric mixer on medium speed for 2-3 minutes until light and fluffy. Add vanilla extract and mix until combined.

Add dry ingredients: With mixer on low speed, gradually add gluten-free flour and salt. Mix until just combined.

Add pecans: Fold chopped pecans into dough by hand using a wooden spoon or spatula.

Shape dough: Place a sheet of plastic wrap on your counter. Transfer dough onto the plastic wrap and shape into a log about 2 inches in diameter and 12 inches long. Roll the log tightly in plastic wrap, twisting the ends to seal. Gently roll back and forth to smooth into an even cylinder.

Chill: Refrigerate dough log for 30 minutes until firm.

Slice: Unwrap chilled dough and use a sharp knife to slice into ¼-inch thick rounds (about 24 cookies).

Arrange and top: Place cookies on prepared baking sheets, spacing them 1 inch apart. Press one pecan half gently onto the top of each cookie.

Bake: Bake for 14 minutes, until edges are just lightly golden. Cookies will still look slightly soft—don't overbake.

Cool: Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.

Dust with sugar: Once completely cool, dust cookies with powdered sugar using a fine-mesh sifter.