In a large bowl, combine the softened butter and granulated sugar. Add the egg, egg yolk, and vanilla extract, and stir to combine.
Cut the vanilla beans lengthwise. Use a small, sharp knife, like a paring knife, to gently scrape out the seeds from inside the beans. Be sure not to scrape off the inside of the bean pod itself. Or if you do, pick that out before adding the seeds to the dough.
Add the vanilla seeds to the batter. Then add the baking powder, baking soda, and salt, and combine.
Add the flour and mix to combine.
In a small bowl, add ½ cup granulated sugar and ½ teaspoon vanilla extract. Stir and mash with a small spoon to combine.Roll the dough into balls with 1½ tablespoons of dough for each cookie. Roll each ball of dough in the vanilla sugar.
Place on a baking sheet. Bake for 8-9 minutes.Remove the cookies from the oven before they start to brown but after they are set on the edges. They will still be quite soft in the middle but will firm up on the pan as they cool. These cookies should be nice and soft.
Notes
Measure by Weight: The best way to get delicious, precise cookies is to measure all of the ingredients by weight. There is no universal way to measure flour, and it can vary widely. I use 140g per cup of flour. If you do not have a kitchen scale, use the dip-and-sweep method used by America's Test Kitchen.
One Bowl For Easy Cleanup: To use only one bowl for easy cleanup, add all the wet ingredients to a large bowl and combine them first. Then add the ingredients that need to be evenly dispersed, such as the vanilla bean seeds, baking powder, baking soda, and salt. Then add the flour last and combine.
Oven Temperature: Ensure that your oven is fully preheated. Some ovens take 20 minutes longer to fully preheat than indicated. Some also run hot or cold or maintain their heat at varying rates. Once you get to know your oven, you'll get a sense for if these cookies take a little more or less time. Pull them out before they start to brown but are set on the edges.
Thin Spatula: To remove the cookies from the pan, allow them to cool for a few minutes first, then use a thin metal spatula to move them to a cookie drying rack. I love to use a metal cheese slicer because it is thin and narrow. That way you can remove one cookie at a time without bumping into the neighboring cookies.
Perfectly Round Cookies: For perfectly round cookies, roll each portion of dough between the palms of your hands to make a round ball. Once they bake, they will flatten and become perfectly round circles. This also creates surface tension, which helps to prevent the cookies from spreading too much.
This recipe was updated with additional notes, testing, and photos in August 2026.