Chewy and delicious, Oatmeal Cinnamon Chip cookies use packaged cinnamon chips, which you can find in most grocery stores in the baking aisle next to the chocolate chips.
Preheat oven to 350 degrees. Line baking sheet with parchment paper; set aside.
In a large bowl, use an electric mixer to beat together the butter, brown sugar, and sugar, until light and fluffy; about two minutes. Then, add in the egg, egg yolk, and vanilla and mix until well combined.
In a separate bowl, whisk together the flour, cinnamon, baking soda, and salt. Pour into the wet mixture and mix until just combined.
Fold in the rolled oats and cinnamon chips. Use a rubber spatula to scrape down the sides of the bowl and ensure that everything is well combined.
Use a cookie scoop to scoop out balls of dough. Roll into balls and place on lined cookie sheet leaving about two inches between each cookie (you should be able to fit a dozen cookies per baking sheet).
Bake on center rack in preheated oven for about 12-14 minutes or just until the cookies are set. Cool on pan for 5 minutes before transferring to wire rack to cool completely.
Notes
If you can't find cinnamon chips, you can substitute with any chip you'd like such as mini chocolate chips or white chocolate chips.
The cookies will be soft out of the oven. Let them cool slightly before moving to a wire rack to cool completely.
Store leftover cookies in an airtight container at room temperature for three days. You can also refrigerate for up to a week or freeze for up to a month.