Preheat your oven to 350°F (175°C). This is crucial for ensuring your cookies bake evenly and rise perfectly.
Line a small baking sheet with parchment paper. This will prevent the cookies from sticking and make for easy cleanup.
In a mixing bowl, combine the melted butter, light brown sugar, and granulated sugar. Whisk until fully blended and creamy. Add the egg yolk, vanilla extract (if using), and whisk again until smooth.
In another bowl, whisk together the baking soda, salt, ground cinnamon (if using), flour, and oats until evenly mixed.
Gradually add the dry mixture to the wet mixture, stirring until just combined. Be careful not to overmix, as this can lead to tough cookies.
Gently fold in the chocolate chips, ensuring they're evenly distributed throughout the dough.
Using a tablespoon or cookie scoop, drop spoonfuls of dough onto the prepared baking sheet, spacing them about 2 inches apart.
If desired, sprinkle a pinch of flaky sea salt on top of each cookie for a delightful contrast to the sweetness.
Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden but the centers are still soft. They will continue to firm up as they cool.
Remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely. Enjoy your warm Small Batch Oatmeal Cookies!
