Step 1: In a large mixing bowl, combine the rolled oats, protein powder, mini chocolate chips (if using), and a pinch of salt. Whisk briefly to distribute the dry ingredients evenly.
Step 2: Add the peanut butter, honey (or maple syrup), and vanilla extract to the dry ingredients.
Step 3: Using a sturdy spoon or your hands, mix until well combined. The mixture should be thick and cohesive, similar to a stiff cookie dough. If the mixture seems too dry and crumbly, add milk one tablespoon at a time until it reaches the desired consistency. The goal is for it to hold its shape when pressed.
Step 4: Once the mixture is thoroughly combined, take small portions (about 1-inch in diameter) and roll them into compact balls between your palms. If the mixture is sticky, you can slightly dampen your hands or lightly dust them with a little extra protein powder or cocoa powder.
Step 5: Place the rolled protein balls on a parchment-lined baking sheet or plate. For optimal firmness and flavor integration, refrigerate them for at least 30 minutes before serving.
Step 6: Store the protein balls in an airtight container in the refrigerator for up to 1-2 weeks. For longer storage, they can be frozen for up to 3 months.