Preheat your oven to 350°F (177°C). Generously grease a 12-count muffin pan or coat with nonstick spray. If using liners, spray them as well to prevent sticking.
In a large mixing bowl, whisk together the milk, eggs, maple syrup, applesauce, and almond butter until smooth and creamy.
Mix in the rolled oats, ground flaxseed, baking powder, cinnamon, vanilla extract, and salt. Stir just until combined.
Gently fold in the chocolate chips, reserving a few for topping if desired. The batter will be slightly liquidy—don’t worry; this is normal.
Use a spoon or scoop to evenly distribute the batter into the prepared muffin cups, filling them to the top to ensure a hearty portion.
Bake for 28-30 minutes, or until the edges are lightly browned and the tops appear set. If the tops brown too quickly, cover with foil during the final 5-10 minutes.
Let the oatmeal cups cool in the pan for 5-10 minutes before transferring to a wire rack. Serve warm or store for later!