Preheat your oven to 350°F (175°C) and grease a muffin tin or line it with paper liners.

In a large bowl, combine rolled oats and milk. Let them sit for about 5 minutes to allow the oats to absorb some of the liquid.

Stir in the maple syrup or honey, followed by the peanut butter or almond butter until well combined.

Add the vanilla extract, baking powder, and salt. Mix until everything is evenly distributed.

Gently fold in the dark chocolate chips, reserving a few for topping later.

Divide the mixture evenly among the muffin cups, filling them about ¾ full.

Sprinkle the reserved chocolate chips on top of each cup for an extra chocolatey experience.

Place the muffin tin in the preheated oven and bake for 18-20 minutes, or until the edges are golden brown.

Allow the oatmeal cups to cool in the tin for about 5 minutes before transferring them to a wire rack to cool completely.