Preheat the oven to 425°F (218°C). Place paper liners into all 12 wells of a standard muffin pan to make the baked muffins easier to remove.
Place the 1 cup plain flour, 1 teaspoon baking powder, 3/4 teaspoon ground cinnamon, 1/2 teaspoon baking soda, and 1/2 teaspoon salt in a medium mixing bowl. Whisk thoroughly so the spices and leavening ingredients are distributed evenly throughout the flour.
In a large bowl, stir together the 1 1/2 cups quick oats and 1 cup almond milk until all of the oats are evenly moistened. Leave the mixture undisturbed for 10 minutes so the oats can absorb some of the liquid and soften.
Add the 3/4 cup packed light brown sugar, 1/3 cup melted and cooled unsalted butter, and 2 lightly beaten eggs to the soaked oat mixture. Stir until the wet ingredients are thoroughly incorporated.
Add the prepared flour mixture to the bowl. Fold gently only until the visible streaks of dry flour disappear. Avoid excessive mixing, as overworking the batter can produce heavier, denser muffins.
Carefully fold 1/2 cup chocolate chips into the batter until evenly dispersed. Divide the mixture equally among the 12 prepared muffin cups.
For a more pronounced chocolate topping, a few additional chocolate chips may be scattered over the surface of each muffin before baking.
Bake at 425°F (218°C) for 7 minutes. Without opening the oven or removing the muffin pan, lower the oven temperature to 350°F (177°C).
Continue baking for an additional 12–15 minutes, until the muffins are golden brown and their centers spring back gently when touched.
Allow the muffins to rest in the pan for several minutes before transferring them to a wire cooling rack. They may be served warm once cool enough to handle or left to cool completely.