In a medium sized bowl, mix together the butter and sugar until smooth. Add the egg yolk, vanilla extract, and almond extract. Mix until combined.
Pour the flour, baking soda, and salt into the bowl and mix until everything is combined. It will seem crumbly at first but continue to mix until it comes together.
Scoop into 6 cookies, about 2 tablespoon of dough per each. Roll between your hands to make them round and place them on a parchment paper-lined baking sheet. Place this into the fridge for 45 minutes so the dough can chill.
Preheat your oven to 350° F. Once the dough is chilled, you can roll the tops in sprinkles (optional) and place them into the oven for 10-12 minutes. Remove from the oven and allow them to cool on the pan for 5 minutes, and then transfer to a wire cooling rack.
Make sure your butter is room temperature. If your butter is too cold, it'll be hard to mix. If it's too warm, it'll be greasy and your cookies will overspread. So what does room temperature even mean? Room temperature butter should be still slightly cool to the touch, and not greasy on the outside wrapper. When you press on it, your finger should leave an indent, but not sink into the butter. I like to take my butter out an hour before I bake. If you find your butter got too warm while sitting out, place it back in the fridge for a few minutes.
Measure the flour correctly. Make sure to measure the flour correctly by using the scoop and level method. If you don't know what that is, you want to scoop the flour into your measuring cup and use a sharp edge to level it off, instead of scooping the entire measuring cup into the flour. This packs the flour in and gives an inaccurate measurement.
Chill the dough. This dough needs time to chill so the butter doesn't melt as fast in the oven!
Use parchment paper when baking. Parchment paper is my favorite thing to use for baking in general, but definitely when baking cookies. Spraying the cookie sheet with non-stick spray creates an overly greasy environment, which leads to super flat cookies. Plus parchment paper makes for the perfect clean up too!