Using a stand mixer, cream butter, granulated sugar, and brown sugar together for one minute. Then add eggs into the mixture one at a time, mixing on low. Add vanilla to the bowl and then begin adding flour, baking soda, salt, and cinnamon. Mix well, then add oats, dried blueberries, and mini marshmallows. Mix until just incorporated and chill for one hour in the refrigerator

Preheat oven to 375 degrees Fahrenheit. Grease the baking sheet. Then, using a medium cookie scoop (holds about 1.5 tablespoon of dough) begin scooping the cookie dough and placing it on the baking sheet (keeping them about 2-inches spaced apart). Once all the cookies are placed on the baking sheet begin to add 2-3 mini marshmallows per cookie--flattening them into the cookie. Place the remaining dough in the refrigerator while the first batch of cookies bake.

Bake the cookies for 10 minutes or until just golden brown. Then remove from the oven, let them sit for an additional 5-10 minutes on the baking sheet (they will continue to cook on the sheet even after leaving the oven). Lastly, place them on a cookie cooling rack. Repeat the step above, until all of your cookie dough has been made.