Preheat the oven to 325 degrees F. Line 2 baking sheets with parchment paper.
Stir together flour, baking soda, cinnamon, and salt in a mixing bowl.
Place butter, brown sugar, and granulated sugar in the bowl of an electric stand mixer fitted with the paddle attachment. Mix on low for 1 minute, then beat on medium for 2 minutes until combined. Stop and scrape down the sides, then beat again for 2 more minutes until smooth.
Scrape down again, and add the egg, beating on medium for 30 seconds. Scrape down the sides and add vanilla. Then beat for 15 seconds more.
Turn the mixer to low and gradually add the dry ingredients; mix until incorporated, about 1 minute. Add the chocolate chips, oats, and cranberries and mix on low until incorporated, about 30 seconds.
Remove the bowl from the mixer and use a rubber spatula to finish mixing the ingredients until thoroughly combined.
Using a small 1 1/2-tablespoon capacity ice cream/cookie scoop, portion cookies onto prepared cookie sheets, spacing them about 2 inches apart.
Bake on top and center racks of the oven for 18 to 22 minutes, switching the sheets from top to bottom and front to back halfway through baking time, until cookies are lightly golden brown around the edges.
Remove from the oven and cool to room temperature on the baking sheets, about 30 minutes. Store in a tightly sealed plastic container for several days at room temperature.