Step 1Heat the oven to 350 degrees.
Step 2Melt the butter in a saucepan over medium heat and continue to cook until the solids have lightly browned and the butter has a nutty aroma, 4 to 6 minutes, stirring frequently. Cool to room temperature.
Step 3In a large bowl, stir together the butter and sugar with a spatula. Mix in the salt, egg, yolk and vanilla.
Step 4In a separate bowl, sift together the flour, baking soda and baking powder. Add the dry ingredients to the butter mixture and mix just until combined.
Step 5Scoop the cookies using a 1-ounce scoop or rounded spoon onto a baking sheet, spacing the cookies about 2 inches apart, and bake until golden-brown and firm on top, about 15 minutes.