2 1/2 cups (354g) all-purpose flour (scoop and level to measure, I like to use unbleached)
1/2 tsp each baking soda and baking powder
1/2 tsp salt
1 1/2 cups (300g) granulated sugar
1 cup (226g) unsalted butter, softened
1 large egg
1 large egg yolk
1 Tbsp vanilla

1. Preheat oven to 350 degrees. Line baking sheets with parchment paper or silicone liners.
2. In a mixing bowl whisk together flour, baking soda, baking powder and salt, set aside.
3. In the bowl of an electric stand mixer cream together butter and sugar until well combined.
4. Mix in egg, egg yolk and vanilla.
5. Add in dry ingredients and mix just until combined.
6. Scoop dough out using a medium cookie scoop (or 1 1/2 Tbsp at a time, and roll into balls if not using a cookie scoop) and drop onto baking sheet, spacing them 2-inches apart.
7. Bake in preheated oven 9 – 11 minutes, they should appear slightly under-baked. If baking more than one batch at once rotate pans halfway through baking.
8. Cool on pan 5 minutes then transfer to a wire rack to cool completely.