In the stand mixer with the paddle attachment, beat together butter and light brown sugar until creamy.
Once the butter sugar is creamy, add in the egg one at a time. Mix until everything is combined.
Next, add in milk, yogurt, and vanilla extract. Mix until everything is combined.
Sift and whisk your dry ingredients (rolled oats, baking soda, baking powder, salt, cinnamon, and gluten-free flour. Then add into the wet ingredients. Mix until you get a thick batter.
With a silicone spatula, be sure to scrape the sides of the bowl to have everything incorporated.
Add in the blueberries (fresh or frozen) and fold it into the batter with a silicone spatula.
Using a muffin pan, (we skipped the liner since we used a silicone muffin pan) and scoop in the batter. Since this is a thick batter fill to the top. This will make exactly 12 muffins. Bake at 425°F for 5 minutes then reduced to 350°F for 20 minutes.
Remove the muffins from the oven and allow them to cool completely before removing them from the pan. Now, you have delicious muffin ready-to-eat! Enjoy!