Add sugar and brown sugar, beat for 2-3 minutes until well combined.
¼ Cup Light Brown Sugar, 2 Tablespoon Sugar
Add the egg yolk and vanilla. Beat for another 60 seconds.
1 Egg Yolk, 1 teaspoon Vanilla
Turn your mixer to the lowest setting and add the gluten free flour, baking powder and salt. Mix until the flour is just incorporated. If you're adding nuts or chocolate chips, fold them in by hand at this stage.
½ Cup Gluten Free 1-to-1 Flour Blend, ½ teaspoon Baking Powder, ¼ teaspoon Salt
Portion into ¼C sized dough balls and place on your prepared baking sheet leaving about 2 inches between. Flatten slightly until the dough ball is about ½" thick using a cookie stamp, fork tines, or your hand.
Bake for 13-14 minutes, until edges are just set. Centers will still be very soft. Remove from oven and cool on baking sheet for 5 minutes. Sprinkle immediately with sea salt, if using.
Sea Salt
Notes
Vegan option: Replace the single egg yolk with 2 tablespoons of non-dairy milk.Peanut free option: Replace peanut butter with your favorite nut butter or sunbutter. My preference is a combination of 3 tablespoon sunbutter and 2 tablespoon cashew butter.Storage: Store in an airtight container at room temperature for 3-4 days.